NL25 rush playing 2nd pair as defender

[babyonboard]

$0.10/$0.25 No Limit Holdem
FullTiltPoker (http://weaktight.com/ftp/)
6 Players
Hand Conversion Powered by weaktight.com (http://weaktight.com/)

Stacks:
UTG MATIZZEN ($53.39)
UTG+1 ramparentator ($25.65)
CO Sir_yellow ($25)
BTN prado cash ($25)
SB Hero ($25)
BB kobila83 ($8.87)

Pre-Flop: ($0.35, 6 players) Hero is SB :qs: :as:
2 folds, Sir_yellow raises to $0.85, 1 fold, Hero calls $0.75, 1 fold

Flop: :jh: :ks: :qd: ($1.95, 2 players)
Hero checks, Sir_yellow bets $1, Hero calls $1

Turn: :4c: ($3.95, 2 players)
Hero checks, Sir_yellow bets $2, Hero calls $2

River: :3s: ($7.95, 2 players)
Hero checks, Sir_yellow bets $3, Hero ???

villain is unknown. thoughts on my play? would you fold, call, or raise on the river?

[tesla79]

I would call. It would be a very weird line especially the flop 1/2 bet if he had a top pair.

Usually I 3bet with AQs against CO, because nowdays many worse hand call you: Axs, scs.

[The teoszan]

I think I would fold this without a read because in my opinion he won`t bet 3 streets with air and what you are beating is basically a bluff.