Ivy touched on many aspects. I would only recommend an overnight with someone you know. I've done 5 or 6. Depending on the person and my energy. One time I spent an overnight where we both slept 6 hours. Another time I had a very hi sexual energy level for a few months, I mean off the charts and spent an overnight with a lady who I knew was a nympho. I think we passed out for an hour and a half and couldn't keep our hands off each other and were going at it again and again.