Sounds like you have a hormonal overload going on. Male will mount a toy if nothing else is avalable...MEN! You might be able to slow this down by shortening thier days. I don't know if you use lights on them of if they are in a room that is very active 'till very late but they need dark and quiet for about 13 hours of the day to get them out of the mood. And Yes..separate your plucker. If you stop it now it may not become a habit with him. If it does become a habit it will be very difficult to stop.