On flush draws and free cards

[TredWel]

This hand came up last night, which made me think about the free card play. Here I've flopped a flush draw, and the person to my right bets into me. I've got position on everybody, and can raise for a free card if I want, but standard flush draw play would say to just call here, hoping the blinds would come along and pad the pot. Raising saves me a SB when I don't complete the flush, but would probably end up with me winning a smaller pot when I do hit.

What's your suggestion for this hand, and does anyone have more general guidelines regarding flush draws and free card plays which would force you to make the field call two cold?

BTW, this seems to be a standard Party Poker .5/1 table. No particular reads on any of the combatants.

Party Poker 0.50/1 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is MP3 with Js, 9s.
1 fold, UTG+1 calls, 1 fold, MP2 calls, Hero calls, 2 folds, SB
completes, BB checks.

Flop: (5 SB) Qd, 3s, 5s (5 players)
SB checks, BB checks, UTG+1 bets, MP2 folds, Hero...