Her mouth turns down in unfortunately the world's cutest pout. He makes a valid point here and Grace is the kind of girl who doesn't mind a hickey so the idea of him not being able to kiss down her neck, or her to kiss his paint smeared chest for that matter... it's not ideal.

Almost nervously, she suggests "Shower?"

It's not nerves or apprehension, only the uncertainty of if changing locale solely so she can get his mouth all over her is going to change the easy, warm dynamic that have going on. Will an interruption derail?