Well it happened again yesterday. I became lucid and right when I did, I felt too tired to maintain it really. First I kept going into third person mode until I forced myself to stay in first person, I immediately thought of trying to do time dilation using a watch or something, but that thought quickly left because I almost completely fell asleep and lost being lucid in the dream.
Then I tried to keep my mind busy by first modifying the girl I was walking with in the dream, then after I finished that I immediately began to start to fall asleep again so I quickly made a second girl and started walking with them, but then I couldn't come up with where we were heading fast enough, so I left the body I was controlling and completely fell asleep, no idea what happened after.

I really didn't go to bed much later than I usually do, so am I just not used to having an active mind in a dream? Usually when I go lucid and am able to maintain it, the dream is scary, so maybe I should try making monsters to keep me awake?

Do you have any tips on how to stay awake during a dream?