Only instances I can see where slowplay = good are when you flop full house plus...and not even necessarily all full house plus depending on circumstances/dynamics, etc.
I'll give one example where I decided to use a slowplay from a session tonight:
Two limps, hero overlimps 6
6
in MP, HJ raises to $15, call, call, frustrated guy says "All in" for $17, two limpers call, hero calls, HJ tries to 3bet but finds out that is illegal, call, call. So $119 going to flop; set mining odds covered pretty well.
Flop 6
4
4
. Check, guy who says he just learned which hands beat which bets out $15. Hero counts his stack and sees we have roughly $250. Call. HJ emphatically declares "all in" for $14 more on top. Folds back to newbie who calls, hero calls. $206 in pot.
Turn J
. Newbie leads out for $50. Hero raises to $125. Newbie scratches his head and calls. $456 in pot.
River 6
. Newbie checks, hero bets last $100, newbie hesitates and eventually calls with 42o.
Against players with even a slightly higher skill level I probably play the flop more aggressively, but call/overcall allows HJ to deposit all his chips with AKo and also allows the newbie to feel invested after he bet/calls flop and leads the turn. He has seen me c-bet bluff a couple times but doesn't realize that I basically never make the turn raise without a boat. Since I hold a hand that can only be cracked by two outers I don't mind playing passively on the flop before waking up on the turn...BUT I would definitely consider playing it differently if I thought the newbie could put the pieces together more effectively.