I was stupid when riding a horse!?help!?

Ok so I was riding my grams gelding and I was bein stupid and let the horse be bossy!I let him leave the rail if he wanted,I let him crib,I let him stop in the middle of the rail!And I let him bolt and rear!:( I'm going back there on Thursday!He now knows what he can get away with!Please tell me how to keep him from bolting on me!Well I know how but even pulling his head back towards my stirrup won't stop him!He's also barn sour!Please help!No stupid answers please!