First time cleaning my gf after another guy.

So for most of my relationship with my gf she has been sleeping with other guys on and off and I've been completely ok with it. Kind of an ask-don't-tell kinda thing. Until last night when she had invited me over to her apartment and when I got there she was completely naked on the bed already. As I approached her and gave her a kiss she warned me that she had already been used tonight. I don't know what it was but in the moment this turned me on so much. As we made out on the bed I could taste the cock on her lips and I started kissing my way down her body until I realized she was actually covered in this other guys cum still. I've never tasted cum before but she looked so good covered in a thick glaze I slowly started licking it up. She started moaning softly and grabbed me by my hair pulling me in more smearing it all over my face. It was so salty and sticky I could feel it getting all over me after a few minutes she pulled me up and began kissing me some more before reaching in my shorts and stroking me to completion.