Since our 1971 Airstream Land Yacht Safari trailer does NOT have a grey water tank, as far as I know, we only have one way of draining the grey water.
on the bayonet twist on shut off clamp, it needs to have a male hose fitting so a hose can be attached to allow the grey water to flow into a portable waste water tote container.
The other option used to be to just leave the hose fitting on the cap open, i.e, no hose attached, so the grey water can just exit flow freely to the ground. But it is no longer legal to do this.
the problem with the blue portable tote, is the inlet opening sits higher than the outlet opening from the coach, so the grey water doesn't flow into it.