Post-Scarif, Cassian gets into a relationship with Jyn or Bodi (or both!) and has his first kiss. He's adorably blushy about it and Jyn/Bodhi assume this means Cassian's a virgin. It turns out he's not. Between missions gone wrong, being a spy, and growing up in the rebellion, Cassian's had a few experiences, none of them romantic. Jyn/Bodhi find out about his past and comfort him, and help him to have a healthy relationship <3

+ other sweet firsts (first date, holding hands, etc.) and Cassian being a jarring mix of innocent and experienced
++ how Cassian actually lost his virginity
+++ there being something in Cassian's past that Jyn/Bodhi have to explain to him was wrong (trading himself for info/food, or draven demanding sexual favors)