Granger in the bath. Forget the Prefect Bath, the Come and Go Room could work wonders with a wish like that. He'll get his hands all in her hair, fingers scraping across her scalp as he massages in shampoo. He can tilt her head back to kiss her, work his way all the way down her neck while he holds her in place. He can glamour his forearm. He'll have to test that to make sure it's solid.