Why does my budgie do this?!?

Okay so my budgie and i allways had a rough friendship, it took him a LONG LONG LONG time (almost 2 years) for him to start liking me, so the other day i noticed he started going on the floor every once in awhile, so i layed down a blanket for me and him to play on. we were playing on the blanket and all of a sudden he lifts his foot and starts biting his toenails really hard and quickly! i panicced and immediatly picked him up and started typing this. by the way i don't clip his toenails he has a perch that grinds his toenails, so could it be him trying to shorten his toenails. could the blanket have been irritating his toenails 'cause of it's puffiness? or is it a behavioral problem like feather plucking?! please help i'm scared that my bird developped a behavioral problem from being scared of me for almost 2 years! he never had feather plucking trouble!