I’d say it counts, personally. No matter how you look at it ERP is only ever a factor if the 2 parties want it to be and it is also sexual in nature because unless there is some sexual gratification the two parties could come to agreement that they pretend ‘it’ happened and if that is not enough I would say there is a deeper reason then ‘its part of the RP’
Then again it wouldnt be the first time one party in a relationship is not getting something they like from that relationship and then seek it elsewhere, as relationship advice maybe try ERPing with your girl, the fact that it is acted out means there is some enjoyment in the act as goes with all things RP
Also consider no physical transgression was made and to liken it to sexting isnt exactly right either because the RP can be considered a factor from the character perspective
Your main priority for your relationship is to find out what she likes about it and see if you can supply it in the future, set up a private discord and go at it (not gonna tell you to do it ingame for obv reasons) and try to find out, walking up to her going “Y THO” will probably set the wrong tone
Who knows, maybe you’ll even get inspired for new ways to do it IRL and increase your lovelife through it
Edit: I dont condone it ingame but outside of it as long as there is mutual consent I couldnt care less