It's not how big her tits are, its whether she lets you play with them. Of you're a submissive, you I guess you're happy to play with them when she lets you
I think its the same as with any other type of relationship; depends on timing and how comfortable you are with your sexuality. If you're not comfortable being a sub, you're more likely to want a professional service where you have some semblance of being able to control when you're not in control. If you've come to terms with your submissive tendencies, I'd think its much more likely you'd want that level of full lifestyle inclusiveness. Honestly, I can't imagine putting up with that shit 24/7, but each to their own. Then again, I'm much more of a give and take kind of guy. So I'm not a bdsm submissive, but with that thread start I had to post. Good luck.