Why Does My Cat Keeps Pleasuring Himself?

My cat consistently, like every night when I lay down to bed, he would jump onto me and starts kneading on my blanket and then humps it, all the while purring loudly and occasionally letting out an unusual meow...I know it sounds gross but that’s that. Anyways, I understand that he’s enjoying himself but, I’m worried that something might be wrong with him, maybe medically, or should I even let him be and enjoy himself as some state that it’s normal cat behavior especially that my cat is not neutered, or should I disturb his deed and teach him to stop doing it. IDK what to do just worried about his health that’s all. Any advice would be very much appreciated.