Speed and Viagra
I don't know about mainlining bleach, but as for meth and Viagra, it may be a stupid idea but there are guys doing it, for exactly the reason this thread was started. The crystal gets them all compulsive and wanting it, but all shrunk up and limp as a noodle. The viagra gives them the boner. There is a back room group sex scene where this is common. I don't think anybody in those situations much minds if their boner won't go away for two days of unprotected non stop fucking. This is one of darker sides of the gay club scene in New York. This drug combo is considered by the Dept of Health to be the contributing factor in the rise in new cases of syphilis and other veneral diseases, and an increase in HIV transmission, which had been declining in the gay male population.
I am not endorsing this, never tried it never will, but it's out there.