How long between sex sessions is it until you get so horny that you're desperate to fuck again? I don't mean so desperate that you'd fuck a dude, but you're certainly willing to considerably lower your standards if necessary (say a 7 is your usual minimum but now you're willing to accept a 4.5).
For me, the need starts to kick into overdrive at around 4 days. After 6 days, it's extreme. This is why I traditionally had stripper fuck dates twice a week.


About 3 days for me - I start feeling super-horny by the 3rd day & beyond.