The victim said he and his girlfriend, Amber Ellis, had been drinking before they got into an argument while walking home to their Tulsa apartment.
The man said he complained about “how needy she had become,” police said.
They continued arguing at the apartment until the 31-year-old Ellis stormed off and slammed the bedroom door.
The victim said he fell asleep on the couch but awoke to find Ellis “biting (his) dick off,” police said.
He fought Ellis off but she hit him in the head with a laptop computer, investigators said.
The man received several stitches at the base of his penis and was treated for other injuries to his head, face, neck, fingers, and knee, authorities said.
Ellis was charged with assault with a dangerous weapon and maiming.
She remains jailed on $25,000 bond.