Tohsaka Tokiomi met up with Irisviel von Einzbern inside the church and asked her to form an alliance with him to defeat the masters of Berserker and Rider.
With both of them beeing mages of the old families they had to perform a ritual.
Because her servant was 'the strongest' Irisviel was allowed to choose how the act would be performed.
Tokiomi, completely sure that she would choose to suck him off, pulled down his pants, revealing his small dick.
Irisviels face turned into disgust seeing another mens member after her experience with Kirei.
She ordered Tokiomi to go down on all fours before beginning to milk him.
With every stroke Tokiomi moaned like a little girl. He lost himself completely when Irisviel used tools to stimulate his anus too.

The alliance was formed: Saber would fight Berserker and Archer would fight Rider.