8 handed. 4 people limp to me in the bb (utg, mp, button, sb). I check obviously.

Flop T62 rainbow

Sb check, I lead, utg and button call.

Turn T626 (full rainbow)

I bet, utg raises, button folds, I?

Reads on utg is that he has made a lot of big street raises, shown down some bluffs, some really strong hands, and some medium strength hands. Can’t think of many natural bluffs and he probably has a lot of sixes.

This is usually pretty strong. Had worst relpos, a chance to protect on the flop, and didn't. So I don't think it's a lot of limpable Tx. You can have most of the strong hands. Have you done anything to suggest you might be foldy? Can you be more specific about the turn bluffs he's shown, ie the kinds of situations he's decided to do that? Some reg types will like fsdr when able to ko a third player.

One bluff he raised with an open ended straight draw 9T on a J8 low low board on the turn, bet and was called on a blank river. On the other hand he had pocket 77’s on a jj934 board and showed after his opponent mucked the river. However the player he was raising was battling/betting a lot when checked to and I had a pretty tight but aggressive image at the time. To that point I had shown down one bluff and a few winners. Not sure if he was thinking on that level but he didn’t seem like a total spew monkey either. Loose and gambly but with some sense of direction.

The way I saw it, he is credibly repping sixes but there was the possibility of some funny business.

As far as being foldy, I had been pretty showdown bound after the flop but had never faced turn aggression to that point. I had been playing somewhat passively on the turn on ugly cards, but mostly in position with four to a straight on board. I hadn’t been getting run over or anything like that.

This is one of those spots where I don't think you're ever supposed to fold at equilibrium, and my guy tells me folding is a big deviation, but it seems like in a live setting they always have it.

I think because you are crediting villain with at least some chance of "funny business" you are deviating too much by making this fold. Sometimes we do not give villains enough credit for correctly surmising that our range is quite weak. E.g., even a pretty braindead opponent is going to assume you do not have any overpairs or TT.

Turn actually seems like a reasonable card to check given your kicker

pretty easy fold

flop could be a bet or check depending on the limpers.