I'm with Maisystar and Flip - I used to lob dirty nappies (enclosed in a knotted carrier bag) out of the cat flap - I could land them right next to the bin.
They would be picked up and put in the dustbin at my convenience. The reason for not opening the door every time is that it has a deadlock and 2 key bolts to undo (paranoia about burglars)
My door and bins are at the side of my house in a narrow passage so not in plain view in the back garden.