basically the story goes, Gudako grailed Emiya to 100 in 1 shot and he felt like shit afterwards saying he needed mana. Gudako misinterprets mana transfer for sex because of Kuro thinking a kiss was all that's needed
@werido12: Hilariously Kiritsugu had at least 5 different women fall for him in different periods of his life. In order, they were Shirley, Natalia, Maiya, Irisviel, & Taiga.
As for Shirou, his own protagonist charm is still strong even in timelines where he never goes through the Fuyuki Fire, like in Fate/Apocrypha:
A certain provincial city. In these novels, the Holy Grail War doesn't occur there, of course, and as a result, the mayor of Fuyuki, Himuro-san, doesn't get a pained stomach from that Great Fire Disaster. And of course, that red-haired boy is living there with his original surname unchanged, but still having a honest and upright personality (as shown in his appearance in Capsule Servant), and likely going through days with a love comedy-like tone, along with a twin-tail magic-fist user and her cheerful little sister who laughs like a high-class young lady.
And if you're wondering who that "cheerful little sister" is: The Tohsaka gave up on the Greater Grail, and now seek a new path in becoming one with the universe with Chinese Kenpou while learning magecraft. The twin-tail daughter of the family might also end up becoming the founder of a “completely new martial arts that combines magecraft and Chinse Kenpou” by the time she becomes a high school student. However, she never imagined that her younger sister who was adopted by distant relatives would come visit her in Japan after becoming a pro-wrestler with unimaginably nice proportions and forming a tag team with a drill-roll-haired girl…!
And of course we know about Archer and his luck with women as well...
Essentially it seems like if you have the last name of "Emiya", you're either a potential harem protagonist or already one. :D