What size bed should I find? I am use to sleeping in a twin size bed, never have...

I am use to sleeping in a twin size bed, never have anything bigger. Most of the time it will be just me sleeping contained by the bed, but I'll probably be having closely of sex with girls so I entail it to be big enough for 2. What would you recommend? Thanks!
How can I find the amount of activeness...
Answers:    I approaching to see optimism. :)

For your own comfort and that of any overnight guests you may have, I suggest you buy as substantial a bed as the room will accommodate when all the other important furniture (such as a dresser, chest of drawers and night stand) is within place.