CO was loose passive fishy type, SB was a nit with a 3bet of ~12%
I looked at the SBs range as pretty wide here, squeezing most if the time. I just called behind thinking CO would come along, and check/folding most flops as he usually does. So I am giving myself some options on the flop by calling the 3bet. Not sure if this is the best option or not.
So then CO shoves. I see a lot of short stacks doing this with all kinds of hands that I am ahead of, and after SB folds, I'm getting ~2:1 so I think it's a standard call.

Poker Stars $0.25/$0.50 No Limit Hold'em - 6 players
The Official 2+2 Hand Converter Powered By DeucesCracked.com

BTN: $79.45
SB: $49.50
BB: $54.30
Hero (UTG): $156.55
MP: $59.95
CO: $31.75

Pre Flop: ($0.75) Hero is UTG with J J
Hero raises to $2, 1 fold, CO calls $2, 1 fold, SB raises to $8, 1 fold, Hero calls $6, CO raises to $31.75 all in, 1 fold, Hero calls $23.75

Any thoughts, or is this pretty standard? I just wasn't sure about the call behind on the 3bet. Not sure if I should've just shoved.

played it well imo. i think a shove would have been spewy