Call down this lagtard?

[why4duck]

4-8 B&M; table's tight/passive in most places. Villain's a prototypical lagtard. For the last few rounds he's either hitting the flop big or backing into ridiculous draws every other hand.

Table folds to hero in CO w/ AJo - raise. Folds to lagtard in BB who calls.

Flop (4 SB): 3 5 5 rainbow. BB checks, hero bets, BB raises, hero 3 bets, BB 4 bets, hero calls.

Turn (6 BB): brick. BB bets, hero?

I know lots will say that a call or raise here is spewing, but the c/r, 4 bet on the flop smacks of desperation. No way villain doesn't 3 bet PF w/ a bigger A or a pocket pair heads up. With a 5 he's check raising the turn for sure. Given my read a better play may be to call the flop c/r and raise the turn, but I'm pretty sure this guy will fire every round on a bluff, including a 3 bet on the turn. And, yes, with most players I would've just called the flop c/r and folded the turn UI.