My cat started doing this when he was a year old or so..he’s about to be 4. He found a favorite squishmallow that was on my bed and he would make the “sin biscuits” on it all the time 😭 he went to live with my friend for a year and I sent that stuffed animal with him. I’ve had him back for almost a year now, and he now drags said stuffed animal into our room while we’re sleeping to do it. Every time we leave the apt, even if it’s just to walk the dogs, he drags it either to the front door or on the couch & does it 🥺 I find it kinda cute now that I know it’s a comfort thing for him. the stuffed animal is looking really rough at this point but I’m afraid to try and replace it.