Okay.... I'm a devout Christian, and I've never tried this act... but I wanted to say that the bible verses in Leviticus do not seem to be about your period, to my understanding. They talk about a women with an "issue of blood" -- that means a blood DISEASE. To me, it was saying in the Old Testament that women with a blood disease were unclean (as were most ALL of the dieseases in the old testament). Let's also remember the woman with an "issue of blood" (in the NEW Testament) that was seeking to touch the hem of Jesus' garmet to be healed -- if "issue of blood" means menstrual cycle, then that makes no sense (you don't need to be healed of that, every woman has that -- IT'S NOT AN ISSUE). Issue = Disease. It even states it as a sickness in Leviticus. Just wanted to clear that up - atleast that's how I see it - I could be wrong (figure it out for yourself). Even though many "translations" act like that's what it's saying - I don't feel like it's saying that. Maybe that's just me. Either way, alot of the old testament laws do not apply to Christians after Jesus came. He set the record straight, so go by HIS words.
AND according to those SAME verses in leviticus, if this were true, she is supposed to quaratine herself and not go out and not touch anything that anyone else will touch -- so therefore we'd be sinning if we went to church on our period and people sat on the same pew as us. I mean really?? Then you're already sinning if you're worried about those verses in that context (which I still don't think they are).
SOMEONE PLEASE CORRECT ME IF I'M WRONG -- but that's how I take it. I only go by the KJV.
However I will say that sex should be between a husband and wife ONLY (which IS biblical). Sex in this manner is not sinful - sex outside of marriage however is sinful. THIS is what you should be worried about.