I played around as a bull for a while back in my youth, but quit after a bad experience. The cuck decided he wasn't okay with the arrangement after all and jumped me (it was their first time). As one might expect I was pretty well distracted at the time since I was balls deep, and I took a few good hits. I managed to interrupt the attack by grabbing his chastity cage and yanking on it, which calmed him right down. I left and settled the affair with them over messager the next day; got what I considered a fair price for my troubles and busted face.
My nose is still a bit crooked from it. I just tell my friends I got it from a bar fight, they've all got super hot wives and girlfriends and I just don't want to give them any ideas...
My recommendation for anybody playing around with the fantasy - try other types of kink together first, get A LOT of practise in communicating your feelings to your partner, especially the stuff that's a bit unpleasant to deal with. If you're not able to be totally honest with them (and more imporantly able to trust them to be totally honest with you), you're wading into deep waters blind, deaf and stupid, and are liable to lose the relationship you have. There are lots of happy, stable couples who do this on the regular, and the reason they're able to do it and stay together is because a) they're both into it in a compatible way and b) they communicate, they talk it out, they tell each other how they feel and they make their boundaries clear so there are no "oops" moments (e.g. you can fuck em but no kissing; no surprise visitors; they can't have a bigger cock than me; no flirting outside the scene; etc. etc. You know, stuff that people have these odd emotional hangups about but might be too embarrassed or ashamed to say otherwise).