Gallirei makeout session.
I should explain that up until this point, they’ve been sleeping together but are definitely not a couple. Reiner’s reaction is extreme, he is so desperate for affection and love in any aspect of his life, and up until this point he’s never been able to get it (except for from Bert). Galliard is slowly starting to acknowledge this side of Reiner, and is surprised byt how much he likes it.
Under the cut is the headcanon/drabble behind this specific scenario. Thanks to @alinajames