Caffeine for attaining lucidity?

I know there's probably a million threads about caffeine and lucidity, does anyone use it regularly? It seems like every time I'm super tired and I go and take a nap after trying to wake up from drinking coffee, I either go into SP or I experience HI which I never do otherwise. In fact, the only times I have ever experienced SP or HI is when I'm on lots of caffeine and take a nap. I haven't even been trying to LD for months, and I almost had a LD this afternoon from doing this. Turns out that after I experienced HI, I thought I woke up but in retrospect I was dreaming.