What is it mean: i was hitting up guys Somebody wrote me: cant really remember how i got ur username.. but recently i got out of a relationship and i was hitting up guys i thought were cute lol...so u single? What is it mean: i was hitting up guys?

what construction have these sentences? I know construction: to have smth done. It means somebody do smth for you instead of you. But what means this sentence and what roles were applied? She is getting her hair done. Susan is having her make up done too.