Bunny humper help

Sigh. The humping has begun. According to the vet we must wait till the first week of June to spay lily (born 1/12/16). Wednesday is spayed and extremely docile.

They're bonded. Lily started humping her today. Wednesday could care less for the most part but eventually gets annoyed and tries to leave. Lily ends up pulling her hair.

Keeping them apart all day is not possible. Lily sleeps in a pen but she's got too much energy to stay in there much longer. Wednesday is pen free and will flip out if contained somewhere.

is hair pulling bad if the other rabbit never gets aggressive? does it get worse if we let her hump her and not stop it? Believe me I want her spayed ASAP but they won't do it yet.