Really annoying cyber-ual harment?

i keep getting youtube messages from thig guy i have never met in my life. im 14 andhes probably 34. im telling to stop hes really making me mad but he wont. he laughs at my pain and keeps telling me offensive things about my gf and i with this sick twisted fantasy that we will be together and my gf will be his maid and he will us every night. that horrible, i dont want the cops involved, ive tried ignoring him but hes reallt p!ssing me off! and yyoutube doesnt have a thing where you can block messages. i jsugt want him to get it out of his head that i dont love him. he keeps saying sick twisted things like 'its ok baby i want to rub your p*ssy and make you scream* and cybering like that and its reallt creepy.