My exhusband use to get it often when we had extra long sessions and I got too dry for him before he got the ky. Even during the "dry times" of no sex at all, many things would caused it for him: different laundery detergant or fabric softener, dirt or chemicals on your hands when you take a piss, jackingoff and not having enough lube or oil,are just what comes to mind at the moment. It would just come and go.
Damn, I'ld ride you any day though baby!