I feel like ice cream has the most potential to be eaten in a sexy way. I mean, you can lick it, suck it, whatever.
Bananas and hot dogs are both bitten, which doesn't seem like it would be all that appealing (especially for a man who's fantasizing that the object is his penis). Between a popsicle and ice cream, I just think that ice cream is the more versatile in the ways it could be sexy.