Funnily enough, it's not messy at all. I think the plunging action creates a barrier, so there is very little blood loss. A towle under the woman provides extra security.
It's up to the individual, and probably the "safest" time of the month if a woman isn't taking contraceptives. Surely a person can wait a few days though???
Just read this post and had to laugh at the oral sex comment. Many years ago, I went under the covers to go down on my girlfriend, had a good nosh, and enjoyed it too because she tasted sweeter than normal. What I didn't know until after I came back up was that her period had come on as we were doing it, and my face was covered with it. Well, she always got a bit wet, so how was I to know....
bms, i always seem to be more up 4 it when i'm on....its very anoying! me and my fella used to do it during, but sadly no more!!!! But it can be a touch messy!