"Parrot" joke

A man suspects his wife is having an affair, so he goes to a pet shop to buy a parrot. Not having much money he chooses a male parrot with one leg.
He takes the bird home and ties its penis to the perch in the bird cage to allow it to stand.
“When I go to work you keep an eye on my wife and tell me what happens” the man told his parrot.
When the man returns from work later that day, he asks the parrot if anything happened when he was out.
“Well” said the parrot, “the milkman came to the door”.
“Then? ” demanded the man.
“Your wife went to the door. ”
“Then?? ”
“She let him in. ”
“Then what? ”
“They started making out in the living room. ”
“Then what? ” cried the exasperated man.
“Then I got a hard-on and fell off the perch! ”