I externally masturbated on someone's clothes on the floor so I had to throw them away.
Did you do this on purpose?
Actually no, I was just drunk that day.
Whether you were drunk or not, it is improper to ejaculate on other's property. Defiling others people's stuff will destroy your relationship with them.
It's fine, it was an accident.
I get it was accident but imagine they found out. They would think it's extremely disgusting and be very upset with you. If you can't handle your alcohol I would recommend you no longer drink.