If you are one of the lucky ones with a higher than average PH inside your vagina and the pill is from a good batch, try it once.
otherwise the average vagina is too acidic for proper absortion of mdma, and u may get an low grade infection from it. (think burning while having sex)
id advise to avoid.
as for plugging, forgeth the enema, if your plumming isnt at its best, just dont plug.
the pill probably wont hurt his penis at all unless its scratched a bit. but still wait 10-15 before anal to give some time to start dissolving.
once you feel the slight burn, you can probably start ;-)
be safe