I don't think it should be anything implying he should "stay" because he never said he was leaving. Maybe something along the lines of "LES-TICLES! LES-TICLES! LES-TICLES!" Or something gay like "WE LOVE LES".
Yes. If I am to yell something gay, I prefer to do it with 92,000 other people so it won't feel as gay.
What about, when they start lining up in the tunnel, the stadium simply starts chanting "Les, Les, Les......" and speed it up a bit until they start running out. Its simple, easy to understand and would spread quickly through the stadium. Now if there is a easy way to get the word out. If some students get it going in the student section it will spread and plus it is on that end of the tunnel.