Sid's Closet

1. impact play, sting: whippy/slappy ruler/micro-paddle
2. impact play, thud: the hard spine
3. light sensation play (light scratching, drawing across skin)
4. heavy scratching (hard)
5. pain play: cf clothespins (multiple possibilities there)
Bondage play:
6. bit (as in bridle)
7. predicament bondage (balanced object)
8. anchor for hair bondage

ETA:
6b. gag
9. pain play: set comb in hair, twist; allows you to do hair-pulling on someone with very short hair!
(#9 was my partner's idea)

. . . and we haven't even started considering potential applications for CBT.