Post mission, they're both on a blood-pumping adrenaline high and immediately set to tearing each other's clothes off and going at it. Partway through, though, Nicky crashes and falls asleep pretty much right when they get to the good stuff– in the middle of getting fucked/sucked off/etc.

Would prefer no hurt feelings or offense; Joe thinks it's more funny or cute than disappointing. Whether this ends in somnophilia or gently tucking Nicky into bed is up to the author.