Need help with DILD mantras

I am not sure if this is the right forum to ask this, but here I go.
Every time I am lying in bed, trying to lucid dream, I go on and repeat a mantra inside my head, such as "as soon as I dream, I'll do a reality check". But here's the problem: After a few minutes of repeating said mantra, it gains some sort of annoying musicality and it loses its meaning. I don't know if I can explain that properly, but it's kinda like when you repeat a word too much and it loses its meaning. changing the mantra a little bit doesn't help either. How am I meant to fix this?

Don't worry about fixing it; it is not broken. The first couple minutes the word hold meaning, but you want to become drifty and begin falling asleep. The mantra should not be actively making you focus or think. If it is taking on a chanting or music like quality, that is ideal.