We have a not quite 1yr old neutered boy. We just got a 6yr old ex-breeding girl. She is very new so once she's settled in we will neuter her. Should we sod the settling in period and get her neutered straight away? Obviously I'm not worried about a litter as my boy is neutered and they are indoor cats, I'm just thinking it might help this behaviour. That said, she doesn't seem to mind, she sticks her behind in the air for him to mount her! Why are they doing this? Is it ok? Do I need to neuter ASAP? Thanks.