It's just masturbation using a toy/item-of-choice.

Choosing hair could just be a person's prediliction. "paraphilia" is where a person needs/uses a certain item in order to achieve erection and/or orgasm. Hair-fetishists have a paraphilia for hair.

It's not necessarily 'having sex with a clump of hair,' but using that hair as part of a masturbation fantasy.