I'm thinking of coming on a public toilet seat
why do you want to masturbate on a public toilet seat ?
I want to leave a lasting mark.
It is inappropriate to masturbate in public and considered lewd behavior which might be illegal. It is fine to masturbate in the privacy of your own home, so do it there.
I think I am a good looking guy, what can I say? I can't help myself sometimes.
You should think about how this will effect the person who comes after you. Please rethink doing this.