REM rebound is when you deprive yourself of sleep, say you lose around 5-6 hours of sleep or more. The REM Rebound part is when you get a whole lot of sleep just after losing a lot of sleep, resulting in longer REM periods. If that makes sense.

Basically, you lose sleep for the first 1-2 days, then you sleep for like 12-14 hours on the following day which leads to longer REM periods.

And for the THC part, most people find that weed makes your dream recall bad. For me it does. Even if you did have a wonderful lucid, maybe even a lucid "high", you probably wouldn't remember it unless you did a WBTB in the morning, which would also probably be very lucky.