Live 2-5, V is a little aggro preflop, no other reads. V opens to 25 in the cutoff, hero 3bets KdKh to 75 on the button, V calls.
(150) Flop is TcTd5s, he checks, I accidentally check it back.
Turn is 8c, he checks, I bet 90, he raises to 300.
In your experience, what fraction of the time do you think this is a bluff?