The only thing new about
Genital to Genital frottage is the name "stripper slide".
You may not like it, but please be realistic about it. If you are in business as a sexual provider, you can expect clients to ask for lots of things that you may or may nor be comfortable with. It is no big deal: just politely say no.
There is no reason to be offended if a client asks for this, and you should not try to make him feel guilty or ashamed for asking...either verbally or as in this case, whining about it in a thread.
There are lots of sexual fetishes that I don't really get, but I truly feel that if it is consensual, people should be allowed to partake without a lot of flack from others trying to impose their own beliefs on them.
If you are not comfortable doing it, then don't do it. It is that simple.