I need help

I always get so horny when i think about eating my own cum and i have done it once 2 years ago. It was legs head and what landed in my mouth i swallowed, but i havent been able to get myself to eat it again. Every time i get horny and i lick the precum off my finger but when i cum on my hand or try legs over head i just chicken out. Any idea why i do it or how i can fix it?