NL25SH JJ gets donked on Q high board
 

PokerStars No-Limit Hold'em, $0.25 BB (5 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Hero ($25.45)
SB ($40.65)
BB ($50.80)
UTG ($20.05)
MP ($18.20)

Preflop: Hero is Button with J[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/club.gif[/img]. MP posts a blind of $0.35.
<font color="#666666">1 fold</font>, <font color="#CC3333">MP (poster) raises to $0.5</font>, <font color="#CC3333">Hero raises to $1.5</font>, <font color="#666666">2 folds</font>, MP calls $1.

Flop: ($3.45) T[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP bets $1</font>, <font color="#CC3333">Hero raises to $3.5</font>, MP calls $2.50.

Turn: ($10.45) 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
MP checks, Hero checks.

River: ($10.45) K[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP bets $2.25</font>, Hero calls $2.25.

Final Pot: $14.95

1st Hand vs this villain, he posted the blind in CO. I wouldn't have called half psb or more, but for 6:1, I thought calling is good.

I was afraid he donked the Q, and not a draw, but should I bet again on the turn, maybe for free SD and to protect the pair?

Re: NL25SH JJ gets donked on Q high board
 

It looks like he has a Q. He did lead out on the flop and called your flop raise. Although his turn check is a little odd to me unless he figured you would bet or raise anyway.
The river call seems a little considering the K and Q and his lead out on he river.

Re: NL25SH JJ gets donked on Q high board
 

Feels pretty much like a QJ type of hand that he wants to keep a small pot with.
And the river bet is a possible blocking bet from him.

Could be a really bad played flushdraw or a A6/76 type.

I would play it pretty much the same as you did. If you later on get a read that he donks weakly you could start betting the turn here.

Re: NL25SH JJ gets donked on Q high board
 

I might raise a little more preflop $2 - $2.50 but this line is fine...you see enough random junk on the river you have to call getting these odds but MP is usually going to flip over Q8 ish.