I can and frequently do leak copious amounts of pre-cum when limp, but it normally involves having been hard first. If I bone up for any length of time then it starts; if I have a good lengthy wanking session it leaks like a tap; and it keeps seeping out slowly for maybe thirty minutes or an hour after I ejaculate.
The one exception is when I use the communal showers at the gym. On the one hand, I've been using open showers on and off for decades and I'm so used to it that I seldom ever get horny at all whilst I'm actually in them. It's all very matter-of-fact and certainly not for sex. On the other, communals occupy an important place in my erotic imagination and, when I'm not actually in that environment, I sometimes watch locker room porn or simply fantasise about all the filthy stuff I'd enjoy getting up to with hot blokes in steamy showers.
The net result of this is that I'm entirely habituated to open showers, I enjoy them as a form of relaxation, I'm comfortable around other men in them and I don't get hard or do anything else I shouldn't in them - however... my Cowper's glands seem to be connected to the place in my subconscious that's screaming "hot shower fucking!", with unpredictable consequences. Sometimes I don't leak at all, other times there's one or two little strings, and yet others it feels like there's about half-a-pint of the stuff trickling out of me. And I have to be a mite careful getting towelled down and dressed after I shower because, if I am going to leak, I don't know when it's going to get started. The towel has had to be used to deftly intercept little wetnesses on numerous occasions in the past.