Rape fantasies are very common in bdsm. Gay men act them out quite commonly, sometimes complete with abductions. With a male sub and fem dom it's trickier, unless you're the sort of guy who could plausibly be overpowered by a woman. If it's just you and a femdom, probably the best way is to have her using a fake gun or knife and threaten to 'kill you' unless she gets what she wants. Or maybe she 'drugs' you and ties you up and then uses you. There are certainly femdoms who would play out a scene like that. My suggestion would be to put up a personals ad on a bdsm-oriented site like Fetlife, Alt.com or so on.