Does it hurt when u sit on your butt after a bbl?

Your butt will likely be sore for several days. maybe longer.  Usually after a few weeks you can sit on your buttocks.

The answer to your question is that it will not be very comfortable to sit on your buttocks directly after a Brazilian butt lift. I usually have my patients avoid direct sitting for more than a few minutes at a time for 4-6 weeks after their surgery. The theory behind this is that you don't want to put too much pressure on the newly grafted fat as it may compromise its healing and ability to live in its new location. The best positions after this surgery are laying on your stomach, standing, or laying on your side (unless a lot of fat has been injected into the side of your buttocks). It's always best to check with your surgeon regarding his/her specific instructions.