Sion shook at the touch of Akiha's lips, and it traveled down her body and into Akiha.

The process here, though, should be elementary. Sion's lips moved to kiss Akiha on the neck, below Akiha's ear. While she did that, her hips lifted up slowly to pull out of Akiha, only to slowly push back down again, being gentle to make sure Akiha was certainly used to it.