Is it normal to cum onto your aunts underwear?

ok guys so i have a real fetish with my aunty. Shes not super hot but theres just something about her that gets my pennis stimulating. To be honest when ever i see her i want to just pull out my pennis and start masturbating over her. whenever im at her house and no-one is around i take a look in the laundry basket and see her dirty underwear in their. she must wear her underwear in the shower because they are always wet everytime. So what i tend to do is hide the wet underwear in my pocket and go to the toilet. Then i start masturbating and finally cum all over her nickers,what really gets me going is that sometimes i actually see cum already in her nickers which means she had recently been masturbating by herself this makes me want to just confront her about it and maybe she will get horny for me.