I've been thinking whether or not post about this but anyway.
I have done this, not with prossies but with civvies and I found out that it does nothing for me. Moreover it turns me off.
The eagled eyed amongst you may have noticed I posted before that I used to hunt for lovers (usually bored married women) in between punting and swinging, etc. So I met this pretty, petite, sweet looking, woman around my age, etc. After the obligatory dinner, drinks, etc. We got to fuck, the first time was OK, a pretty vanilla affair. It must have been good for her so we decided to meet again but this time she asks me to be rough, OK I don't mind a bit of rough sex so that was good too.
We had a few fucks like that until one day she says she wants it really, really rough and asks me to slap her while she is kneeling in front of me and me forcing her to suck me. OK I say let's go along with that. The idea seemed fun to me at first. So off we go and then I slap her (a bit gently) and then she asks me to do it harder and harder. The problem is the more she asks me to slap her harder the more I keep losing wood and feeling uncomfortable. We did finish having a bit of rough sex (I had to do a bit of DIY to get wood again) later on she said she enjoyed that. I asked did you really want me to slap you harder because I was feeling a bit uncomfortable with that. She said what we did was fine but I could sense she didn't get what she was expecting. Anyway, we never saw each other again after that.
Second time, a few years later, this time with a long term lover. We had been going out for some time and were experimenting with different fantasies, etc. We had been swinging, done group sex, etc. Next she says it was rape role play she wanted to try. And guess what was her fantasy, she is a prostitute that comes to my room (in a hotel) gets my money then refuses to fuck me so I then have to "force" her to deliver the goods.
We had a safe word for this because by this time I was more clued up (and so was she). Anyway she changed into some "hooker" clothes, goes out the room and a few minutes later knocks on the door. Initially it all goes as planned, I give her the money, then she changes her mind and tries to get away from the room. I grab her, we struggle and by fuck, she puts up a really fierce fight. Up to this time I was taking the whole thing mockingly but she was really into the role. So I then have to force her to the bed and start ripping her clothes off as agreed (thus her changing into her hooker clothes) she then starts swearing at me and I swear at her back and it goes on for a bit. I managed to rip all her clothes off and stretch her legs open but no point, as my cock remains as limp as a wet rag.
Fuck I thought, why can't she just say the safe word, FFS so we can fuck normally! Anyway she continues to struggle and swear at me then she lets me keep her legs open, I knew she was expecting me to fuck her by now, but no chance with my limp dick so I decided to fist her. The look of surprise on her face was priceless, I reminded her of the safe word and she nodded but no safe word uttered, oh bloody hell by this time I was knackered and sweaty but enjoying the fisting. I managed to get my whole fist inside of her and it felt weird and good at the same time. She stopped struggling and we did manage to have a good fuck. I had to go up her arse (after a bit of DIY to get wood again) as her pussy was sore (and loose probably). During our post coital chat she said she really enjoyed that I told her I enjoyed it too but it's really not my thing. We never did that again once she ticked it off her list.
After those two experiences I don't think I will try them again, it's not for me and it just turns me off and it's embarrassing losing wood but I suppose it was another thing to tick off one's list.