we were meditating while laying down.Eh, I don't think that's possible. How could you fell asleep while your kundhalini energy is going upper on your spine? That's not possible.
Unless you were in meditation state, then yes. Or maybe it wasn't sleep and you just crossed the line. Anyways, you have me interested now, cause I have been doing yoga for the last 6 years and this is the first time i heard someone falling asleep during a class.