I have a very soft brush and very gentle; mainly I groom with my fingers, though. Either way, she loves the feeling, and it was one good way of bonding with her. She seemed to be very accepting re. my grooming her, no matter how I did it.
The folks at the rabbit shelter where I got her knew that she enjoyed grooming sessions and encouraged me to pursue that once I had her at home. She was at the tail end (no pun intended) of shedding her winter coat, so I did a lot of gentle fur-picking. She wallowed in all that attention!