You cannot normally cast Shocking Grasp while you're pinned because it has Somatic components. When pinned, you are limited to spells that only have Verbal components (or no components), or Material components but only if you already had it in your hand before you were pinned.
If you somehow could cast Shocking Grasp (perhaps using Still Spell), and you make the required Concentration check, then you would still not be able to make an attack (touch attack) to deliver the spell - it doesn't just automatically go off because your enemy is grappling/pinning you.
Leaving aside the question of how you are able to cast the spell, the question is still a bit unclear. Touch attack rules do say:
"If you touch anything or anyone while holding a charge, even unintentionally, the spell discharges"
This certainly doesn't seem to extend as far as it could be interpreted. Most casters are touching the ground all the time for instance, and it doesn't seem to apply when someone attacks you in general, even with natural weapons. I would say that it is limited to you purposefully making contact with another creature or object, although I'll admit that it is hard to square that with the unintentionally part of the phrase.
Normally delivering a touch attack is an action, either a standard action or a free action as part of casting the spell. Pinned doesn't have deliver a touch attack as one of the actions it allows. A creature with a natural touch attack couldn't attack when pinned any more than a creature holding a dagger could.
It is possible that a GM might rule that if you have a held charge of a touch spell, like shocking grasp, that when struggling to escape or perform one of the other allowed actions you might 'unintentionally' discharge the spell. However, I certainly wouldn't count on that happening.
unintentional touches and accidental command words for items just don't actually work in the game. You either enforce actions to do things, or you allow players to skip and get free actions.
I always interpreted that bit ("If you touch anything or anyone while holding a charge, even unintentionally, the spell discharges") to mean:
If you deliberately touch anything, generally with your hand, while holding a charge, the spell discharges - this requires the usual attack roll if you're trying to touch an enemy. Also, if you accidentally touch anything, such as stumbling and accidentally using your hand to catch yourself, the spell discharges - this requires the usual attack roll if you accidentally touch an enemy or even an ally.
I've never interpreted to mean "any incidental contact with anything discharges the spell".
Furthermore, the spell REQUIRES an attack. It's just a touch attack, but that requires an action (even if it's just the free action granted by casting the spell) which requires the caster to make an attack roll to hit. None of which is included in having an enemy make an attack or CMB roll against the caster.
There's no freebies here. Holding a touch spell is not a license to automatically damage your attackers nor does it allow you to deliver the the attack without attacking.
I always interpreted that bit ("If you touch anything or anyone while holding a charge, even unintentionally, the spell discharges") to mean:
If you deliberately touch anything, generally with your hand, while holding a charge, the spell discharges - this requires the usual attack roll if you're trying to touch an enemy. Also, if you accidentally touch anything, such as stumbling and accidentally using your hand to catch yourself, the spell discharges - this requires the usual attack roll if you accidentally touch an enemy or even an ally.
I agree with you in general.
If though a wizard has been holding a shocking grasp charge, gets grappled and pinned, and then, still holding a charge, makes an escape artist or a combat maneuver roll to get out of the pin, I might have it go off. I'd think about it.
I always interpreted that bit ("If you touch anything or anyone while holding a charge, even unintentionally, the spell discharges") to mean:
If you deliberately touch anything, generally with your hand, while holding a charge, the spell discharges - this requires the usual attack roll if you're trying to touch an enemy. Also, if you accidentally touch anything, such as stumbling and accidentally using your hand to catch yourself, the spell discharges - this requires the usual attack roll if you accidentally touch an enemy or even an ally.
I agree with you in general.
If though a wizard has been holding a shocking grasp charge, gets grappled and pinned, and then, still holding a charge, makes an escape artist or a combat maneuver roll to get out of the pin, I might have it go off. I'd think about it.
Would you also have it shock the wizard since he's in direct contact with the target? That's kinda how electricity works - we could say the spell's magic insulates the delivery hand when you make an attack roll to deliberately touch a target, but if that target has wrapped his arms and legs around you in a grapple and you accidentally touch him somewhere, wouldn't that electricity flow through both of you?
Maybe.
No rules for that, just like there aren't really any rules for accidentally zapping an enemy without making the attack roll first.
It's a bit of a dangerous precedent. Not like I think that mage would walk around holding a Shocking Grasp charge all day in case he gets grappled, but the greater scope of allowing a touch attack to be delivered DEFENSIVELY and WITHOUT AN ATTACK ROLL (or even as part of a different roll with a different objective) might have farther reaching ramifications.
I've always taken the prohibition as the reason that you can't use the appendage for anything else. If I've got a shield in one hand and a held charge in the other, on my new turn I can't spend a move action to open a door, five foot step through it, and touch attack the orc on the other side, because I'd discharge my held charge when I touched the door.
As a HOUSE RULE, I require the caster to choose an appendage when he casts the spell. That appendage is busy holding the spell until it is discharged, but the others (if any) are unaffected.
Other people allow the held charge to be "free-floating", usable with any appendage the creature possesses and movable between them (even between attacks in a full-round attack). This seems too permissive to me, because you'd never be affected by the accidental discharge provision.
Other people allow the held charge to be "free-floating", usable with any appendage the creature possesses and movable between them (even between attacks in a full-round attack). This seems too permissive to me, because you'd never be affected by the accidental discharge provision.
Especially since you can deliver a touch attack as part of an unarmed strike, and an unarmed strike could be any part of the body, e.g. a head butt or a kick.
If you can freely rotate it, then the wizard / monk holds his wand in one hand and has shocking grasp in the other. He moves to the foor, moves his "held charge" to his foot, then while standing on one foot he opens the door. Finding no one on the other side, he move the "held charge" back to his fist, and moves to the other room. Finding something interesting to pick up, he does so, moving the "held charge" to his forehead, or his elbow. That gets ridiculous, IMNSHO.
The discharge guidelines for a held charge are clearly supposed to provide some sort of limitation on a character's actions and consequences for violating them (losing the spell).
Would you also have it shock the wizard since he's in direct contact with the target? That's kinda how electricity works - we could say the spell's magic insulates the delivery hand when you make an attack roll to deliberately touch a target, but if that target has wrapped his arms and legs around you in a grapple and you accidentally touch him somewhere, wouldn't that electricity flow through both of you?
Maybe.
It's a bit of a dangerous precedent. Not like I think that mage would walk around holding a Shocking Grasp charge all day in case he gets grappled, but the greater scope of allowing a touch attack to be delivered DEFENSIVELY and WITHOUT AN ATTACK ROLL (or even as part of a different roll with a different objective) might have farther reaching ramifications.
I didn't say I was sure. I also didn't say defensively. My example was CMB or escape artist to get out of a grapple, which are there own standard actions, and CMB is basically an attack roll, with escape artist being an alternative set of bonuses for the same action.
It isn't without other precedent. You can make a natural or unarmed attack while hold a charge and if the attack hits you deliver the spell and your charge. If a wizard was initiating a grapple while holding a charge, I would allow the spell to discharge on a successful grapple attempt, as being quite similar to a natural or unarmed attack in that way. The main difference between that and my example is I don't know that I would require the attempt to be successful, but other than that it doesn't seem like a big change from the rules and I don't think it would create any dangerous precedents.
I would never have a touch spell discharge because of someone else's action, only the person holding the charge.
I won't comment on your whole 'electricity shocks everyone' other than that isn't what the spell does. You usually present better arguments than that.
A spellcaster can cast a spell with touch range (like a Shocking grasp) while this pinned, like Pikachu, sending touch attack by the body part that is touching the Grappler, or the instant when it is hit.
Thanks, now all I can picture is "Pikachuuuuu" as the verbal component of all electricity-based spells...