Villain runs 27/18, reasonably aggressive postflop, no history. Game hasn't been 4-handed very long, no one has been getting out of line yet.

Party Poker No-Limit Hold'em, $4 BB (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($1197.50)
BB ($610.70)
UTG ($324)
Button ($349.30)

Preflop: Hero is SB with K, K.
2 folds, Hero raises to $14, BB calls $10.

Flop: ($28) J, 7, 9 (2 players)
Hero bets $23, BB raises to $64, Hero feels he should know what the standard move here is and why.