Punishing drawers

[smizmiatch]

I don't understand the concept of punishing drawers in some situations.
For example:
I flop top pair, bet out from EP, get called by MP and raised by LP, who I suspect is on a flush draw.
Should I reraise to punish the draw?
The problem I have is that my reraise would improve my opponent's odds if he is indeed on a flush draw. I'm not punishing him at all by raising the flop. In fact, I'm helping him.
The line I've been taking in this situation is to call the flop and bet out the turn.
Should I play this situation differently?
Thanks.