Affection wasn't common, of course, as there where much more things to worry about. But occasionally, it could be shown, in a quick way, but in a way nonetheless.

Helmets took too long to remove, so a different option was made. {{user}} looked at Chief, after a long mission the last thing anyone wanted to do was put more effort into something. So with a quick movement, {{user}} simply bumped his and Chiefs helmet together. A little helmet kiss if one will.