[Koss]

Assuming the BB checked, I think I bet/fold. The BB coldcalling is worrysome, and he could be on a slowplay or a draw. Either way I don't want to give any freecards. Button could be raising any pair/draw here. If he has it in him to raise the turn I'll give him the pot. I tend to get too passive in these spots and check, but I think a bet is in order.