My girlfriend and I have been dating for over a year now and so far, the sex has been great. Recently, however, she's suggested that we become more experimental. She wants to tie me to the bed and do things to me like drip candlewax on my nipples and attach a string to my penis that she can tug on. She thinks that such things will be able to "heighten sensitivity" and make our sex even more stimulating. I don't have anything against these goals, but before I get into something unusual, I'd like to know whether this type of behavior is healthy.

I've been thinking of different things I can do to please my girlfriend when we hook up, and one thing that's come to mind is while administering cunnilingus, maybe I could suck on a menthol cough drop. I think that would feel pretty cool. Is that safe? Is that abnormal?