I had my boy Teddy neutered the first week I got him. Had him for 4 months. Now he is biting my sofa throw pillows and cat beds/blankets, making biscuits on them while he is grinding/humping on them.
Casper Making Biscuits
He does it because he feels safe and comfortable. If your kitten makes biscuits on pillows and snuggles in blankets, it is because you have provided for him and given him a good home where he can be happy.
You are a good “cat mom” and that is one way how cats say, “I love you.”
Chester (fixed) used to try and hump on my feet in the bed until I took in Meep. Now he bothers her (she's fixed too)!
In her case, it seems to be a dominance thing. When on top, he acts like he doesn't really know what to do. She only takes it for a little while, then bites him to shoo him away. He gets along with her just fine 99.5% of the time.