when you say "hooking up", i'm under the impression that you mean getting some play...so, with that train of thought...i used to cultivate in hopes of eventually hooking up, and tho it's worked from time to time i've determined that it's not worth it, total waste of time and for some it's a waste of money as well, so i would just be straight up about my intentions, whether it be thru flirting or otherwise...so here's an example of what i found works better for me:
depends on the situation, environment, etc...but let's just say that i do meet someone at a bar and she starts talking to me, i'd most likely imply from the fact that she's talking to me in that setting that she's looking for some kind of attention...then she tells me she has a bf...so one of two things:
#1. i convey to her by flirting that i'm interested in hooking up with her, she turns me down, i move on and forget her
#2. i convey to her by flirting that i'm interested in hooking up with her, she flirts back and maybe gives me the greenlight, i go for it
yes with #2, i'd be invading someone else's nest, but it takes two to tango and she was advertising by reciprocating the flirting...the choice to partake in infidelity is her own and chances are if it wasn't with me, it'd be with someone else...
btw: i don't do any of this anymore, i feel pretty settled with my current gf
i would've voted if you had a choice similar to: Go for it, if it doesn't work out then move on and forget about her...