I went to my parents in laws house this weekend and when I was changing my 10 month old sons nappy, both my parents in law came rushing over leaning over LO and start stroking his bum, my MIL then proceeds to kiss his bum and tickled his nipples when I was changing his clothes. Whenever my partner holds LO she constantly sniffs his thighs/bum (clothed) saying mmmm and when she holds LO she will swing him to FIL so he can smell him and say mmmm. I didn’t bring it up at the time as it was my partners birthday so didn’t want any arguments (which I know would probably happen if I mention to MIL). I told partner after and he said he doesn’t find it strange but will tell them not to. I obviously understand a mum kissing/blowing raspberries on her own baby’s belly/bum to make them giggle but this is just making me very uncomfortable and would like to hear other people’s opinions.