Green’s Dictionary of Slang

1. the human nose.

1906

Comic Section N.-Y. American and Journal 13 May 1: I wish I were on top of that dear ike’s peak!

2. (drugs) the central two hours or so of an LSD trip when the hallucinogen is at its most powerful.

1971		E.E. Landy Underground Dict. (1972).
1981		D.E. Miller Bk of Jargon 343: peak: That point in an LSD trip in which its continuously increasing effects reach their height.