New to Cuckolding as a Bull

I’m new to cucklold as a Bull. I recently talk to a married couple on a swinger website about being play partners. They are looking for a bull because there last one have moved out of town. I plan to meet them soon. I recently did two MFM threesomes lately but nothing as this extent of ordering a man around while fulfilling his wife’s needs. I did talk to wife and husband about sexual activities they are okay with and limits. Any advice?