100NL- Pretty certain this is standard OESD + FD material
 

Poker Stars - No Limit Hold'em Cash Game - $0.50/$1 Blinds - 5 Players - (LegoPoker HH Converter)

<font color="black">SB: $95.00</font>
BB: $133.65
UTG: $102.40
CO: $105.10
<font color="black">Hero (BTN): $120.95</font>

<font color="black">Reads: </font><font color="blue">Villain is 37/13/1.5 over 500 hands</font>

<font color="black">Preflop:</font> Hero is dealt 4[img]/images/graemlins/diamond.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] (5 Players)
2 folds, <font color="red">Hero raises to $4.00</font>, <font color="red">SB raises to $8.00</font>, BB folds, Hero calls $4.00

<font color="black">Flop:</font> ($17) K[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">SB bets $8.00</font>, Hero calls $8.00

<font color="black">Turn:</font> ($33) K[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">SB bets $12.00</font>, <font color="red">Hero raises to $37.00</font>

What's the best raise size here?

Re: 100NL- Pretty certain this is standard OESD + FD material
 

has the villian made this donky three-bet much?
I think your raise is ok against his awful turn donk-bet, but his AF is low and his silly little bets are consistent with his small raise preflop so I doubt we have much info about his hand.

This could easily be AK looking for value (albeit badly played) and I would often be happy to flat call the turn.