I like it when they are fucked so hard, maybe selfishly, that they can't stay hard. Me, I like to not work it in slowly. Put the tip up to the hole and push all the way to the balls in one quick push.
The top was supposed to take all the cum from the bottom and lubed his own cock up more and fucked him more using the bottoms own cum as lube. At least that's what I would have done.