both people stand sideways, both with the same lead leg (so their stomachs face opposite ways essentially)
for an extra challenge, drop into a low horse stance.
start with a large space (maybe a foot or two) in between the two people
take turns going back and forth trying to touch eath others shoulder with a backfist (open hand so you dont kill your opponents shoulder)
the person defending should try to rotate their upper body to move the shoulder out of range.
start in side horse stances with opposite lead legs. (stomachs facing same direction)
person A tries to kick the back of person B's lead leg (go for the thigh - you can hurt the knee) with a lead-leg roundhouse kick.
person B tries to pull their leg back before it gets hit. start by doing this any way you want, then try to do it by pulling up into a cat (cat-foot, flex-t, nekoashidachi, etc) stance.
drill 3: (this is one played as a pain game outside of martial arts, but its applicable)
person A stands squared up with person B, both in a natural shoulder-width stance. person A puts his hands out palm-up. person B puts his hands directly above person A's hands, palm-down. there should be about an inch of space between person A and person B's hands.
person A attempts to slap teh back of person B's hands. he/she can go one hand at a time, both, or can cross hands as well (hit person B's left with A's left)
person B attempts to withdraw his/her hands before they get hit.
when person B successfully does so, A and B switch roles.
the quicker you are and the better you can read your partner, the less your hands hurt.
variations for any of the drills:
1. change the method of withdrawing the attacked appendage.
2. bring a third person in who uses a signal to indicate to both people when person A will attack. this will work person A's reaction time at the same time. (thanks to the_mad_elf for this idea)
3. blindfold the defender. (to work sensitivity and make sure the other senses are tuned in)
4. blindfold the attacker (provided they have decent enough targeting not to hurt their partner). this will allow the attacker to feel more where he/she is telegraphing.
hope that helps someone. feedback?