Slowplaying bottom set with 2 suits on the flop

Here I took a turn from the normal pot-flop, push turn kind of play. In retrospect, yeah... I should've bet out etc. But I'm not sure it would've had the same effect. Normally, I don't slowplay with draws up.

PokerStars No-Limit Hold'em, $0.25 BB (8 handed) converter

UTG ($24.25)
UTG+1 ($38.65)
MP1 ($18.70)
MP2 ($15.45)
CO ($58.45)
Button ($33.90)
Hero ($24.35)
BB ($42.80)

Preflop: Hero is SB with 3[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/spade.gif[/img]. UTG+1 posts a blind of $0.35.
UTG calls $0.25, UTG+1 (poster) checks, <font color="#666666">1 fold</font>, <font color="#CC3333">MP2 raises to $1</font>, <font color="#666666">2 folds</font>, Hero calls $0.90, <font color="#666666">1 fold</font>, UTG calls $0.75, UTG+1 calls $0.75.

Flop: ($4.35) T[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, UTG checks, UTG+1 checks, <font color="#CC3333">MP2 bets $2.75</font>, Hero calls $2.75, UTG folds, UTG+1 folds.

Turn: ($9.85) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $4.5</font>, <font color="#CC3333">MP2 raises to $11.7</font>, Hero calls $7.20.

River: ($33.25) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>

Final Pot: $33.25