Flopped bottom two against a 2p2 Tag

[Chipspin]

Regular loose game at the Oaks 15. Directly to my right is Bdaddy, a TAG who posts occasionally and we even frequently IM each other from work (what else is work good for?) about hands we played the night before.

PF: Three limpers, Bdaddy completes in the SB and I check the BB with 76o.

Flop: Kh7h6x, two hearts.
Bdaddy bets, I raise, all fold to Bdaddy who 3-bets, I 4-bet, he 5-bets, I?

I can't think of one hand I'm ahead of here. Even 9h8h I think he just calls the 4th bet instead of 5-betting OOP...