To most people, marijuana is considered a gateway drug that leads to other drugs. "Jumped The Gate", or "Jumping The Gate" is when considering one individual experiences a drug, at first, that is something other than marijuana as their first drug. Double Jumped The Gate and other variations are counted until a person experiences marijuana. That is when "Going Through The Gate" or "Gone Through The Gate" is applied.
"when did you Jumped The Gate?"
"When i took ecstasy and shrooms before going through the gate."