The 1st time I dumped my gray/black tank, I made quite a mess. The connector came off the hose when I pulled it tight. Parkliner
now puts a tie wrap on to prevent the connector from pulling off.
The other problem was that I needed to hold the hose in the drain or it would pull out from the water pressure. My arm isn't long enough to reach the drain release on the trailer while holding the hose down. So I tied a 6' piece of rope to the drain release. Now I can stretch the hose out, insert in the hole, and then pull the rope to open the drain release while still holding the hose in place. No mess at all this time.
This is intended for those newbies like me that are getting ready to dump their tank(s) for the 1st or 2nd time. I also avoided using the toilet for #2 until I was sure I could dump the tank without making a mess.
ETA: And keep a pair of disposable gloves in the tube. Wash them off after use and keep as emergency gloves in case you forget to replenish them before next trip.