Michael Doherty of 64, Ballyarnett Village in Derry was charged with the offence that was said to have occurred on November 8.
A police officer connected Doherty to the charge and opposed bail.
The court was told that the boy and two of his friends were playing in the Glen Road area of Derry.
The boy then became separated from his friends and went to the house of a female friend.
Doherty was drinking there and gave the boy four shots of alcohol.
The female in the house became concerned about the boy's presence with Doherty and texted a neighbour who came and took the boy who was then re-united with his friends.
The court heard that a short time later the three boys were making their way to one of their houses when they met Doherty who was 'very drunk and very aggressive.'
The 15-year-old tried to calm the situation and led Doherty away from his friends.
At a corner Doherty was alleged to have grabbed the boy by his hair pulled him to his knees and the alleged oral rape was said to have taken place.
The boy then went to his friend's house and disclosed what had happened.
Doherty was granted bail of £1,000 to an address in London that Doherty could be bailed to.
He was ordered not to enter the North except for court and not to enter Donegal at all.
The case was then adjourned until December 4.