It's random, but you really shouldn't be getting rained out
that frequently... Rain always occurs on Day 5, but from what I can see in the game code, there should only be an 18% chance of being rained out any other day of the week. Are you having that issue on
every play-through of the game?
The deepthroat scene: You have to have gotten more than 5 blowjobs from her already. Then go through the Living Room "wacth cartoons" scene again, pull her dress up to get a better view when she dozes off, then go finish yourself off in the bathroom.
Catch her with the vibrator: Ignore temptation and keep watching the movie, then when you wake up and notice she's no longer on the couch, go investigate the noise coming from her room. However, you must
not have the vibrator in your inventory; if you've already found it in her room and
confiscated taken it, or if you used the cheat menu to give yourself all the inventory items without having to work for them
, you won't catch her playing with it because she won't have access to it anymore after you take it.