Stopping a horse from puffing his belly

One of the common problems lots of people have when saddling their horse is when the horse puffs his belly up. Sometimes the horse will take a deep breath when you're tightening the girth. When you're done tying it, the horse will release his breath, and the girth will hang loose. This will cause it to slip when you're putting your foot in the stirrup.

Usually, the reason horses do this is because you've been tightening the girth way too tight. So they puff themselves up to make the girth looser. When you're saddling the horse, poke his belly to make him exhale (this doesn't hurt the horse). Tighten the girth to where it's snug, but not pinching the horse and causing it to be uncomfortable and in pain.
If possible, warm the horse up before you ride by lunging him and doing ground exercises with him. You should be able to see if the horse has puffed his belly because the saddle will fall sideways or be extremely loose on the horse's back. Before you mount, tighten the girth. Poke the horse's belly and make him exhale.
Be careful when you're in the saddle. If the horse has puffed his belly up, the saddle may slide sideways, taking you with it. Grab the horse's mane and get your feet out of the stirrups. Then you can slide off the horse's back and reposition the saddle.