I don't know of a curved tip coupler. I end up stooping down to the level of my counter to do anything on the sides - not the best method. Some people use a turntable that you can angle to the side but I've seen mixed reviews about them (have not used it myself). Good luck! I'd love to hear everyone's advice.
I just checked eBay and there are a couple of people selling them. Just search - angled coupler Wow, I just checked and one is already gone and the others are charging $8.00 for shipping for one coupler