I like gradual shrinking; with several sizes throughout the story / picture series / video. Usually; the smaller he ends up the better.
I'm with coolingb on that one. I imagine that slowly shrinking over time would make the reality set in more. From starting off just noticing that she looks taller then to being able to see she is significantly bigger, then noticing your clothes don't fit would start things off right. Then maybe a drastic drop from like 5 feet to 3 feet with the lady getting even more menical. As things start to heat up, knee high then to ken doll sized. The whole proccess to me seems so hot. Not a quick proccess though, maybe over a couple of hours. Shrunk down all the way untill she'd have SUV sized nips.
On the other hand maybe just into a bowl of cheerios. Like it would be our choice anyway, lol.
