Paint straight line at ceiling like pro without tape. Paint ceiling first, wrapping corner. Take ubiquitous back edge and gently score mark. Just use corner as naturally flowing guide. Using brush loaded with paint, just cover line.
Cover your trampoline springs with pool noodles. I was pinched in springs so often when I was a kid. This is safe and looks awesome. Now I just need a house with a garden to put my pool-noodled trampoline in.