I could be wrong, but I suspect even a lot of straight guys would enjoy doing this! If you are totally straight and agree with this, please respond with a "Yes".
This reminds me of things my friend and I used to do when we were young (a long time ago). I loved the feeling of his hot cum splashing onto my dick! And of course I was happy to return the favor, with his cum as lube when I stroked. Damn, I miss those days!