
Wonderstell |

Here's an official Paizo ruling on the subject of multiple sneak attacks per round.
Sneak Attack: Can I add sneak attack damage to simultaneous attacks from a spell?
FAQ wrote:
No. For example, scorching ray fires simultaneous rays at one or more targets, and the extra damage is only added once to one ray, chosen by the caster when the spell is cast.
Spell-based attacks which are not simultaneous, such as multiple attacks per round by a 8th-level druid using flame blade, may apply sneak attack damage to each attack so long as each attack qualifies for sneak attack (the target is denied its Dex bonus or the caster is flanking the target).
There you go.