For number 1, I'd say not to shy away from making the guy look awkward during sex. Realistically, most people will be awkward one way or another. There are some erotica that focuses on the reactions of the guys, and often times, they do look kinda ridiculous, shy, idiotic, and girlish. It's a private moment of vulnerability.
But if you want to go for some level of sophistication, the thing that makes that awkwardness stand out less is the interaction between the two partners. If your guy and girl are having sex they both want to have with each other, him being excited and flustered can come off as "cute and adorable", "annoying" or "way too fast", depending on the character of the girl.
So you kinda have to develop your girl's reaction as well. Why is she not as excited? Does she actually want to have sex with this guy? Is she just nervous about the whole thing? is she more experienced than him and just find his reactions adorable/annoying?
The key is to have their reactions bouncing off each other. Show body language as well to give cues to the readers that "hey, they're into each other".
As @kip said -- break up the reaction into pieces.
Personally, meaningful reactions are broken down so you can see the gradual change from emotion to emotion. If he's shocked+ pleased, you could do 2-3 panels showing his change from shocked to pleased, with his body either relaxing or tensing up. It helps to hold in the moment and slow down the pace of the story, especially if he as a character is too excited and is rushing.