Found fic: Arthur thinks they are in a relationship but Merlin thinks they are not

[cheeseontoast1]

Trying to find a specific fic I remember reading. I think it was canon era. Arthur and Merlin have been having sexual encounters for a while, but while Arthur thinks they have mutual feelings for each other, Merlin thinks that it is casual/that Arthur just expects him to serve him sexually. Merlin finds this difficult to bear (since he does have feelings for Arthur) so avoids looking at him/kissing him. They have secret touch signals that indicate when either of them want something sexual.

This comes to a head when Arthur comes up behind Merlin while he is standing on a chair and embraces him and asks him why he never looks at him while they are involved. Then the truth comes out and Arthur is horrified. At the end they realise they both have feelings for each other and make up.

Really grateful for any help in finding it and apologies if I've misremembered any of the details!

Update: found