this happens to me if I think about the dream right after waking up - and if I fall asleep shortly after. I dont think I can reenter it hours later..I would have forgotten too many details

Sometimes I'm so sleepy when Im thinking about the dream, I've already fallen asleep. So when I go back into the dream I trace my footsteps to really remember what happened. Its kinda like exploring a movie set. But when I explore the old dream, I never continue where it left - I sorta restart it and do things differently