Here are some places I've found this sweet Giles:
The Practically perfect series by mythichistorian. Pythia aka mythichistorian is maybe my favorite Giles writer.
Not even the rain by Denorios. Schmoopy, yes, but this Giles blushes and mutters.
The hogs beneath the skin by Gileswench.
Friends and lovers by Rari.
Teacher's pet by Rari.
Baby Love by Reni. This one is a response to one of my favorite challenges: see what happens when Buffy and Giles have to cope with age-regressed Scoobies.
Finding the center by Luce.