This person, at first glance, seems to be willing to trade some form of intimate relations for a bicycle of equal value. At $1000 it must be quite a position. I don't even know what a Frenchi over/under is but it sounds quite satisfying and maybe slightly acrobatic.
Alas, after some Googling I think the person meant Franchi Over/Under, as in an antique shotgun.
Sex or guns? Insert your own euphemisms in the comments section.