Mine was laundry detergent.
My thing with detergent started very young, from infancy until I slowly did it less and less and stopped at about 9. I didn't do it for about 9 years and then started again at 18. It lasted another year and I don't do it any more now.
My mom used to give me a washcloth fresh from the dryer to suck on when I was young and they always had the taste of detergent still on them. I think I just associated them with comfort after awhile.
If you want to know the names the big ones are: