How do you get a couple of hundred posts without knowing this? Maybe I've been doing this too long...
"Russian" (fucking her tits) is included in the bodyslide (BS) ONLY IF she happens to perform that service.
In other words, some girls simply don't do that, no matter what session you take. But a girl that DOES offer "Russian" pretty much won't do it if you're just getting a NR, nude or topless.
One other twist: it's a lot more common for the girl to be on top (or alongside) you while you have your cock between her tits. What they're really scared of is having you squirt your cum on their face and hair. So even if you pin her down, climb aboard and start fucking her sternum like an dog in heat, she'll likely put a hand at her chin in case you cum like a porn star.
Of course, in the above scenario, she would have already kicked you out of the room for pinning her down, but you get the point.
One other note: Russian is pretty common with a BS. Maybe 75%.
One additional note: you do have to ask for what you want. You're paying, but that doesn't mean she can read minds. If the girl never says no to any of your requests, you're not using your imagination!