Thinking about Grimmjow being more or less a ghost in the living world.
Grimmjow got bored so he's sitting on Ichigo's dresser half watching him and half watching over him, not quite comfortable enough to fully mirror him but enjoying the Shared Company. He senses another hollow nearby and flares his reiatsu in warning, before reining it back in to avoid waking Ichigo.
Ichigo wakes up in the middle of the night for some reason he can't quite place, and he's still so sleepy and comfy cozy so he just stays there, half awake and daydreaming. He's sleeping on his side facing the wall and doesn't even bother rolling over hes so comfy. For some reason he's thinking about Grimmjow, and he's got the worst morning wood about it, but he's still too sleepy to do anything about it other than press his thighs together and half grind against himself.
Grimmjow noticing the little movements Ichigo is making in his sleep have gotten less random, and he smells oh so sweet now. He's never been one to not take what he wants when he wants it. He enjoys fighting Ichigo though, and doesn't want things to end. Maybe he even cares a little about Ichigo's opinion of him.
But Ichigo whimpers Grimmjow's name, and it's over.
Grimmjow suddenly appearing behind Ichigo, phasing through blankets to get at his prey. One hand shoving Ichigo's shoulder so he's flat on his stomach and another grabbing his hip to pull him up into a position Grimmjow favors.
Ichigo never sees him coming, but he knows exactly who it is manhandling him, and the little yelp of surprise is chased by a moan almost as delicious as he smells.