Drawy board with bottom pair and position on Turn

[NIX]

UTG is a main reason I'm at the table. He is running at 51/13/.9 over about 75 hands. If the board isn't too scary/draw heavy, he'll peel flops and sometimes turns with as little as one overcard. I've seen him showdown with as little as 4th pair in these cases with the pair not always being made on the flop and him not always getting agro with his big pairs, especially when he turns them. If the board is scary, he's much more reasonable and hasn't shown down anything in these cases that wasn't a flopped moderate draw or made hand. Even with how loose he can be postflop, his WTSD number isn't absurd at 35% (although this would mean he does showdown somewhat often based on his VPIP).

SB is unknown.

Full Tilt Poker
Limit Holdem Ring game
Limit: $0.50/$1
5 players
Converter

Pre-flop: (5 players) Hero is Button with A[img]/images/graemlins/diamond.gif[/img] 7[img]/images/graemlins/diamond.gif[/img]
UTG calls, CO folds, <font color="#cc0000">Hero raises</font>, SB calls, BB folds, UTG calls.

Flop: T[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/diamond.gif[/img] 7[img]/images/graemlins/spade.gif[/img] (7SB, 3 players)
SB checks, UTG checks, <font color="#cc0000">Hero bets</font>, SB calls, UTG calls.

Turn: 4[img]/images/graemlins/club.gif[/img] (5BB, 3 players)
SB checks, UTG checks, Hero ???


I've felt lost in these spots of late and tend to bet this heads up. Are we still doing this threeway and what is our river plan?