I think we sorta pick our "spots". For example, if we're both home and our son is in school that day, we consider that "Prime Time"...

Or lining up our "Fun Time" with our child's bedtime..and checking in with each other to know if we're energetic enough to have sex..

I also think it's kinda important to expect to be interrupted and have a sense of humor about it and a LOCKED DOOR.