Curling -- viagra didn't do a lot for me at 50 or 25 mg. What did do a lot for me is clitoral stimulation during intercourse. I don't want to make this too much like a sheets thread, but I've found that while it's nice if my partner touches me there, the best guarantee is for me to do that part myself, and let him concentrate on other things. After all, women have more erogenous zones than men have hands!
I think a lot of women might be shy about doing that though, considering that a pretty big percentage won't even admit to masterbating, lol.
Is your wife bold enough for that?
Wyst