Before!! That way if he’s like “oh well that’s why I wanted to hang” you don’t have to awkwardly leave or wtv. If he gets pissy abt it that’s his problem, if he wants to hang non sexually then that’s good. Also I came from that other girls post and I hate that she was so mean to you. Communicating beforehand is always the best option, but she didn’t have to crash out on you for not knowing what to do here.