Reaching down, grasping the balls firmly (to remind oneself of virility/desire to grow), and letting out a warcry before each meal can help. No, it doesn't matter if you are in public- people will respect or GTFO real quick.
Ok but for real- when eating to grow, solid food is way better than just shakes. Don't go to a full liquid nutrition plan or anything, but do try to have at least a couple of shakes each day, and use them to sneak in some calories from EVOO/EVCO. You can also throw natty nut butters in there (this is actually fucking delicious). You can also just throw down a spoonful or two of natty nut butters outside of shakes to get a lot of cals.
Don't get crazy paranoid about macros if you're trying to gain. As long as you get ENOUGH of each macro, you'll be fine (as in don't worry about going over or consuming a good amount of fats, etc). Getting in a lot of carbs is the hard part, assuming that you don't eat complete shit. It's one of those things that you get used to over time. I've found that the harder I work in the gym, the easier it is to put huge meals down afterwards. So as long as you work hard and eat as hard as you can manage on the carb front while supplementing with cal-dense fats to fill in any missing calories, you should be good.