How to tell him I like it a bit rough?

So I have recently started this kind of fwb thing. Its pretty straightforward no strings attached situation. We dont really text unless its to meet up and then after we dont hang out or anything which is fine I dont have time or looking for anything else. We have hooked up maybe 4-5 times and its good but I like it a bit rough and now I dont know how to address it for next time we meet. How can I tell him? Do I text him or just bring it up next time we meet?