Sexy turns into WTF

[aK13]

Stars 3/6 6max 6handed

CO is an annoying LAGTAG 29/19/2.2 over about 250 or so hands.

Folded to CO who opens, Button folds, SB folds, I call in the BB with 8[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/club.gif[/img]

2 to the flop for 4.33SB: 9[img]/images/graemlins/heart.gif[/img] 8[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/club.gif[/img]
I bet, CO raises, I 3-bet, CO calls.

2 to the turn for ~5BB: 3[img]/images/graemlins/diamond.gif[/img]
I bet, CO calls.

2 to the river for ~7BB: A[img]/images/graemlins/spade.gif[/img]
I check, CO bets, I sexy, CO 3-bets, and I...?

(pot is ~12BB if it matters) -- Call, cap, or fold?