I really really need help...
Whenever I try a WILD, be it a nap or a WBTB, I just lose my train of thought and think about some random scenario.
Here's what happens:

1) I get comfortable and relax.
2) I start thinking "I'll be aware I'm dreaming. I will have a lucid dream. Relax. Stay focused." or somesuch mantra, and visualize the words while hearing myself say it mentally.
3) Swirly lights appear.
4) My thoughts go off track. "I will be... stay... Kirov Airship reporting! Cool! Bomb his base... uh oh, Apollo fighters... wait, I need to focus..." *fall asleep*

What am I meant to think of while WILDing? How can I stop myself from falling asleep?