What most naturally follows?

How to tell when gerbils are mating
Listen for thumping sounds.
You may also observe the gerbil pounding both rear feet. The sound is usually a quick thump, but can vary in tempo and volume.
This can be mistaken for the gerbil being excited for reasons other than mating. Sometimes gerbils other than the mating pair will " catch on " and start pounding their feet too.