Du,
I think that you are a Pioneer with stating that you want your wife to fuck your ass with a strap-on, and I see nothing wrong with it !
My wife and are swingers (I am not active at this time), but she still is and at the parties, we have many toys and alot of the guys/girls are "bi-sexual" and love to get fucked with our strap-ons, slip on rubber cocks, giant dildos etc . . . check out some of these links to some good ass fucking info.
I have used a dildo and/or viberator in my asshole along with my wife for years now - for our
kegel training sessions - but at this point I have not got fucked with a "strap-on" . . . . . . . . . . yet . . . . LOL.
I say "
GO FOR IT" - make a difference in "
YOUR" life, you only live once, dont worry about what other people say - experience all you can - "
Life is Short Enjoy Yourself"
Just tell her to take it easy on your asshole at first and use lube - you done want any permanant damage to your asshole. My wife is very experienced with anal sex and she loosens up and relaxes quickly. So until you get used to getting it in the ass, you may have to learn some relaxation techniques for your anal sphincter muscles - "Relax" them, its alot easier.
My wife said when she first started letting guys fuck her asshole, she was really scared from what other girls said (in highschool) and she would tense up and expect pain. She said that there was a little pain at first then she learned how to relax her ass muscles and it created orgasms.
When we fuck doggy style, she lets me fuck her ass, then pussy, then ass, then pussy and so on and so on . . . . . . . .
Keep us updated and enjoy the ride. Also, post some pics as often as you can - especially of you getting rammed ! Cant wait to see em'