What do you do when your friend talks repeatably on a subject that is suggestive?

we are friends with a great couple but lately he talks about non stop...about his wife swinging from the ceiling fan among other things. one comment ok but over and over ????? if we try to have a conversation we get interrupted with the same comments...he thinks it is funny. we think it sucks. i am tired of not finishing a sentence without interruption. my hubby and i think this talk should be kept between the two of them. she laughs but we just roll our eyes anymore. they aren't fun to be around anymore. how should we handle this. or maybe we are being too prudish but i don't think so.