I know what you mean! Xander has been doing that a lot lately, too. Only he's been doing it in my hand when I pick him up for his morning bath. We have the routine down: I fill his bath, then open his cage and pick him up. Halfway there, he flashes me and deposits his sperm packages right into my hand. I rush to the bathroom, deposit him into the water, and wash my hands very thouroughly
In the meantime, he calmly poops and replaces all his stuff and waits for a water change or to be taken out of the tub... after which I wash my hands again 
It's funny to think that several months ago we still didn't know if he was a boy or a girl. Guess we know now!
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~Alika~
1.0.0 green iguanas
0.1.0 cockatiels
1.0.0 senegal parrots
0.1.0 blue-fronted amazons
0.0.1 red belly piranha