Communal peeing

Critics agree that Harley is a little outside the norm when it comes to mature kitties.  And his latest quirk?  He likes to pee every time I do.....even if he doesn't have to go.  And if I try to sneak into the bathroom?  He comes running (you'll remember he wears a purple rhinestoned collar with a bell) from wherever he is and takes a running leap into his litter box.  Weird right?  Not only!  The other day someone who doesn't live here was over and used the bathroom (of course closing the door) and Harley was beside himself!  When I went, he actually opened the door while I was doing the deed and took a big leap into his box and squeezed out a drop or two.  Yup, that's my cat.