Aw, Lav, we're just pulling your leg!
On a more serious note: You say the man in question is sitting down when he "schiebt" his right pant-leg up. If he has his right foot, or more precisely, his right ankle, up on his left knee (a common sitting position), then I could imagine him pushing his pant-leg up. If his foot is on the floor, I would expect him to pull up the pant leg. (Or trouser leg, sorry, I forgot you're using the BE version.) Which he could conceivably do, by the way (this is for you, BZL) by grasping the pants near the bottom with a thumb and forefinger and pulling upward. Depending of course on the pants, the leg, the thumb, the forefinger, the kitchen sink and the price of eggs in Denmark. :-)