Hi my horse is a GV x and he's always playing up ( on his own ) unless i take him with another horse... He never wants to work and always rears /bucks :L
HELPPP!
Hey.
Ohh dear sounds unpleasant, i would suggest firstly to alimanate any possible phisacle problems back, teeth, saddle, bit. Etc. if all is well then yes bad manners for sure.
Do you feel more tense when riding alone? How do you react to his behavour?
It could be that you are transmitting to him and he is taking advantage.
Sorry not much use more info needed. X