Me and my ex Teacher?

Ive been hanging with my X teachers family (wife) (kids) a lot after he was my teacher 2 years ago. I befriended him through school were he gave me his number. Couple months ago something happened between me and him, I thought it would be a one off thing because we didn't talk about what happened. But just last week we were snuggling on couch together and he was me again. Im almost 18 and hes twice my age. I dont know were I stand with him or how to ask him whats going on between me and him.