My female cat has started doing this over the last couple of months. We also have a male cat (both indoor only both rescues) who she loves and has known her whole life, sleep together etc. our son is 6 months old in a week or so but she hasn't been doing this since he came home yet I guess it could be a delayed reaction? She does like to sit on me though not all the time just when it comes up her humph but never on my dh. The only other time she did this was when my ils stayed with us when we had a bigger place. She is frightened of strangers if the door goes it's tail down eyes enormous and slinks off. We had just 1 big litter tray with hood but bought another bigger one with a hood a few days ago, both are cleaned fully and clean clumping litter put in. Any suggestions please? She is 3.5 and our boy cat is 5.