The only way you'll be able to get these trophies at this stage of the game, is to get into a scheduled boosting session. You can see them in the right column here:
To lend some detail to the original post:
The glitch allows anyone to shoot through any wall in the game. All they have to do is switch shoulders rapidly. To exploit the glitch, the user just has to see an enemy marked with hawk eye 2/3 (to see their outline) then shoulder swap while shooting at them, even if they are behind multiple walls. You can see what it looks like here at 3:27 and 5:10:
See what it looks like to have it done to you at the 0:34 mark:
This issue is reported quite often on the Reddit forum for the multiplayer. It IS a problem with your thumbstick. It's generally due to getting dirt lodged inside. The reason swapping via the options menu fixed it is because your other thumb stick doesn't have the same dirt stuck in it.