[ReptileHouse]

Raise preflop.

The flop in complicated by the fact that you didn't raise pre-flop. You have two overcards and a backdoor nut-flush draw. Your overcard outs may or may not be clean, especially with the pre-flop raiser raising again on the flop. The straightforward interpretation is that he either hit his hand or already has a made hand. Most likely candidates are AQ, KK or AA. If he's a solid player, he knows UTG+1 is unlikely to have big cards since he didn't raise pre-flop, and so he may be raising a hand like JJ or TT here are well, hoping to fold out one or the both of those of you who follow him.

You have about 4-5 outs to an 11SB pot, so you're getting close to the odds you need to call with implied odds if you hit, but barely. MP3 has yet to show strength, so it's probably fairly safe that this won't come back to you for more bets. If it does, that's going to really suck. As is, it's a risky call, but not a truly terrible one. That said, I probably fold here.

I like the check-behind on the turn. Both the other players in the hand are looking strong enough that a check-raise is a definite possibility. Even if it's not, your fold equity looks to be very low here given the strength shown so far by the other players. Similarly, you're not able to bet for value realistically here, so a check-behind is the logical choice.

Similarly, the river is a solid value bet. You've hit your hand. A check-raise would suck, but it's likely that anyone looking to make that move would have bet out after your check-behind on the turn. A queen pays off pretty often here, as will a lot of other pocket pairs.