I am playing TAG, SB is 24/14/1.5. BB is like 65/30/2.5 and has luck sacked his way to a $1000 stack. I have position on BB and am trying like heck to stack him (I have like $280). He is a total donk, but a bit unpredictable. Anyway, he's the only reason I'm at the table because I would be eating lunch if he wasn't there...

I raise 88 UTG to $8 (hoping to isolate BB), SB and BB call.

Flop is [4s][5h] Pot $24

SB leads $12, BB calls, I fold?

I'm not sure what a passive small blind would be leading with here so I decide to just fold. However, I am not sure what the presence of BB will do to SB's thinking. I think BB being in the hand will make SB do a lot of things he wouldn't normally do as its obvious BB is a donk and everyone seems to be trying to play pots with him (to their peril).

Standard fold?