Doesn't normally happen to me. Which hose size are you using? Which sander? As my sanders seem to have a ridge around the male part which kind of makes it difficult for the hose to fall off.
Then again, I'm using a boom arm so the pressures are different.
In fact, thinking back, I bought the boom arm to stop me dragging the hose off the tools when the hose caught on something. Which was annoying.
So, actually, I know exactly how you feel and this post is pointless, but I've typed it now, so I'll post it anyway.