1. ...let her take a picture of you naked?
Most of the women I have dated have taken naked pics of me so... yep
2. ...get naked in a risky public place?
I'm not really into getting arrested so probably not
3. ...act like a little boy and call her "momma"?
not sure if I could do it while keeping a straight face and not making jokes, but I'll try if I must
4. ...let her give you a spanking?
possibly, I'm not really into pain but after a little bourbon, who knows?
5. ...eat her out until she has an orgasm?
well... yeah! is this even a question?
6. ...masturbate in front of her?
yep, would even include the answer for #1 if need be
7. ...let her pee on you?
hmm, gonna have to go no on this one
8. ...strip naked in front of her friends (guys and girls)?
depends on the situation but probably
9. ...taste your own cum?
maybe
10. ...obey a strict diet and exercise regiment for 3 months?
sure, I try to stay healthy already so what's a little extra motivation???
11. ...dress up like a school girl with a mini skirt, stuffed bra, panties, wig and makeup?
not really into cross dressing, but if it was with a more joking or playful mood, well... maybe
12. ...go without sex or masturbating for 1 year?
not a chance, don't even ask
13. ...let her tie you down first?
yep, will even provide the rope and cuffs
14. ...shave off all of your pubes?
shave completely? nope, can't handle the razor burn. trim really short? already am 
15. ...dress up like a french maid and do chores for her?
see #3
16. ...let her put clamps on your nipples?
just what size clamps are we talking here???
17. ...cum on your own face?
yep
18. ...let her fuck your ass with a strap on?
yes, please
19. ...strip naked on a live webcam?
wouldn't be the first time, so... yeah
20. ...suck her gay friend's dick?
maybe, depends on the friend
21. ...let him cum in your mouth?
same, depends on the friend
22. ...let 5 or 6 of her girl friends fuck you with strap-ons and dildos while you eat them out?
are you really expecting a no here?
23. ...have a threesome with her and her guy friend (you give and receive)?
possibly, depends on the friend
24. ...be her sex slave for 3 months (she gets to do whatever she wants, mix between conventional sex and femdom)?
I could do this
25. ...be her bitch for 1 week (no sex, but a lot of dress up, chores, humiliation, and oral for her and her friends (guys and girls))?
no sex? nope