Jeremy Harris, actor and playwright, was on Late Night with Seth Myers. He was talking about the federal theater project and how enthusiastic he was about it. This is a conflation of “beating the drum for” (promoting someone or something) and “blowing/tooting (one’s) own horn” (boast or brag about one’s abilities). “Beating the bushes” (trying very hard to achieve something) might be in play here as well given the context. And no, the subject was not masturbation. A big thanks to Sam Edelmann who heard this one and sent it in!