As a top, I love watching my bottom cum with my cock inside of him. I not only get the physical satisfaction of nutting in him, but a visual satisfaction also.
Most bottoms like a top that can cum quick so they can move on to the next guy. I am of the mindset that you are gonna have to earn this load. If and only if you are able to fuck someone else when I am done with you then you are a better man than me.
How do you know that you both or neg? Besides he has fucked you already bare so it really dont matter, but you will love the feeling of carrying his seed and being his completely.