I've been sent a hug/flirt what do i do?

A flirt is a way of saying that you find someone attractive and a hug is more about friendship and support. In either case, that person is showing you that they like your profile and they want to see if you like theirs too. At this point, you can either start up a conversation with them by sending them a message directly or you can send them a flirt/hug back to show that you are also interested in chatting to them and put the onus on them to start the conversation. Don't play flirt/hug tennis forever though! If you sent the first flirt/hug and they responded with a flirt/hug you need to fire up a conversation so read their profile again and get some words sent.