you'll have to make a loop in a script:
timer = 0
#loop
timer = timer + 1
~1
t1 playmove "EffectStandSitDown"
?(timer >= 5):exit
goto "loop"
exit
not sure if code is 100% correct, i haven't edited in ofp for a while. also not sure if you still can loop animations, i used this code in ofp version 1.20 before all the other versions came out.
Edit, im not sure if switchmove keeps the dude in teh animation, but it puts teh dude in the position without the animation part