I raise some rabbits. They are semi-free range where they are outside in a fenced in area. The bucks (male) and does (females) have access to each other. It takes but one time for a buck to breed a doe and it all takes place in like a half a minute. She then has babies in a month. A few days prior to the due date, her nesting instincts kick in and she runs around collecting hay and makes a nest underground. She also pulls fur from herself and lines the nest.
Riker and I watched this one female run all over taking the long grasses we threw in their run in large mouthfuls and take it down a hole in the ground. She was obviously creating a nest. She also didn't hesitate to pull fur from other rabbits, a behavior I hadn't seen before but I suppose fur is fur. So with a crazed look in her eyes she kept up this behavior for quite a while (it's so cute really). Suddenly, she jumped a buck, head side, and started "humping" him. She did this for like 5 minutes and he never moved! Usually rabbits don't sit still very long when another rabbit is doing anything to them so it was a surprise that the male allowed this. Then he followed her into her den. We were pretty perplexed since she was already breed, why would she be dry humping a male. For that matter, I've heard that pregnant women also have raised libidos. It makes me wonder what is going on hormonally and neurochemically. As for Riker and I, watching a doe with a mouthful of grass and fur furiously humping the ears of a buck, we laughed ourselves into tears.