threesomes…how? it just doesn't make sense to me.

Goodness, I wish you'd been more specific! So, I'll assume you're asking how a threesome (or ménage à trois) works physically. Considering you can have three women, three men, two men and a woman or two women and a man, the positions possible in all four combinations are … well, very very numerous.

I'll just try to do a basic, vague rundown of different ways a threesome could work … let's assume that any same sex participants are either bi or gay, and that strap-ons and other toys are acceptable to everyone involved …

• The participants can take turns having one-on-one sex, while the third person watches
• If a woman is involved the other two participants can penetrate her simultaneously vaginally and anally (double penetration, or DP, is hugely popular in porn movies)
• Person A can penetrate person B anally or vaginally, while person B performs oral sex on person C.
• Person A can perform oral sex on person B, while person B performs oral sex on person C, and person C can perform oral sex on person A … is your head spinning yet?
• All three people can give each other hand jobs.
• Person A can penetrate person B while person B penetrates person C
• Two people can simultaneously perform oral sex on the third person, while giving each other a hand job …

… and the list goes on. Really, the possibilities are probably only limited by your imagination and everyone's level of open-mindedness. If you're curious, and you're in a relationship, you could mention the idea to your partner and see if s/he might be interested in trying a threesome with you. If you're single, and interested, personal ads (both in newspapers and online) often feature ads from couples seeking a third partner.

Unfortunately, Adam & Eve discontinued Nina Hartleys "how to" videos about threesomes, which would be more entertaining for someone who's just curious, but not really intent on trying a ménage à troi. But if you're actually interested in trying a three-way, Amazon carries a couple of highly rated books on how to start, manage and enjoy three-partner sexual encounters. Threesomes: How to Fulfill Your Favorite Fantasy, which concentrates mostly on two woman/one man threesomes, and The Threesome Handbook: A Practical Guide to SLEEPING WITH THREE. Both books are written by people with experience with menage-a-trois sex and three-way relationships.