33rd President: Harry S Truman, 1945 

Mime = 33 (Truman was the 33rd president)

True man = Truman

Barrel = 945 = 1945 became president

Hairy = Harry 

They all performed a mime (33) of the true man (Truman) with a barrel (1945).

Connect Trueman to Harry

The true man (Truman) had very hairy (Harry) armpits. 

NOTE: The way Mammoth Memory remembers Harry is to think Harry is hairy.