So I'm going to be without my trumpet for two years due to being gone on a mission for my church. Depending on the mission, there's a SLIGHT chance that I might get to take my trumpet with me, but I'm thinkin I won't be able to. Does anybody have any tips on how to increase lip endurance and lung capacity while sitting down or anything like that? I know of the pencil trick which helps great for range btw. Any help will be appreciated, Thanks in Advance my brethren!