8 Max
UTG folds
UTG+1 (Hero) 55 bbs, black JJ, Limps

Splashy player is on the BTN. I've noticed the splashy player likes to raise preflop against limps. He will straddle then raise big against everyone's limps. It appears as if he has been running good tonight with a big stack. I sat down at the table only about 30 minutes ago executing a short stack strategy, and doubled up through him when I jammed over his limp with AJo. I never limp, and only choose to do so here because I can back-raise.

HJ Fold
CO Fold
BTN ("Splashy") raises to 4.75 BBs
SB calls
BB folds

This is my first time limp-back raising, so I do a poor job of calculating my raise. In retrospect, I should make it very big, as I'm OOP, Splashy will call any size, but if I make it too small, then the SB will likely come along as well (he has been active so far).

UTG+1 (H): 3B to 16.5 BBs

BTN calls
SB calls

3 players to the Flop
Pot: 50.34 BBs
Flop: 6d 5h 3h

SB: X
UTG+1 (H) 30.5 BB: All-In for 60% Pot

My thoughts are that it is a wet board. Although it's a MW Pot, at least it's only 3 people, so I think against these weak ranges, JJ may be good enough to go All-In, as it benefits from protection and can get called by worse pairs, and some draws. For example, I think the splashy play's range would connect with many combos of top pair, pair + gut shot, OESDs, or flush draws with 1 or 2 overcards that he will call with, and then I'm ahead.

There are sets, 2 pair holdings that beat me, and made-straights that beat me,
74s - 4 combos,
66, 55, 33 - 9 combos,
65s - 2 combos,
63s -2 combos,
53s - 3 combos
= 20 combos beat me

To find at least 20 combos that he would call and I beat,
A6, K6 = 24 combos
96s, 86s, 76s = 9 combos
...and so on

I think SB also could connect with this range with some suited Ax or Kx, but otherwise he would likely fold his overcards such as KQ, so again betting for protection here is a good idea. However, he also could have called with a bit of a better range than Splashy, with low suited connectors, pocket pairs, etc. that beat me, so I'm not sure if I should be more cautious given it's MW. On the other hand, I'm so shallow anyway, that betting for protection is really appealing.