Why did this happen when I was d?

I was d not so long ago. A man got into the room I was staying at during the summer when I was out at work and was waiting to jump me when I came back home. He had a knife and made me give him after he stripped me. What bothers me and what I don't understand is why did I become lubricated down below while he was making me do the oral on him? When he started to get ready to put his member in me down below he started to like mock me as wanting it because he found it was wet down there and was saying I was all hot and ready. It is something that bothers me because I was scared and everything and did not know this man and did not want him to do this. Does anyone understand why these things happen