How to be a Pos 5?

Hello guys, a have a question as a newbie - should pos 5 always hang around pos 1 at early-mid game and should pos 1 be constantly at his lane to farm creep waves? I'm playing with my friend pos 1 and he constantly complain that i'm not with him after laning stage after he got ganged while being all alone at lane, but i feel like i'm gonna miss impacts on teamfights and if i gonna just bodyguard him we will just feed together, because realistically what could pos 1 and pos 5 do against gang of 3-4 enemies. Thoughts?