The rule of thumb for sexual intercourse , esp. in male homosexual activity , in regards to the size of the giving participants penis.
Whenever the penis is larger then 6 inches, then the receiving participants only agree to receive 1/3 of the phallus of the giving participant.
This rule dose not always apply , as some male homosexual intercourse goes by the 'breath through the pain' rule, and clarification is expected to be communicated prior to the encounter over the interwebz or in eye contact in the nanoseconds before the door closes and penetration occurs .
Kevin Smith was interviewing Malcrom Ingram, as Malcom admitted his dismay upon the idea of accepting a full nine inches of raging man meat. Kevin reminisces of his mothers 'frugality' , gets lost in a haze of 'foggy' memory, then returns to introduce to the SModcast community and the entirety of the internet the 1/3 rule.
Kev, this is for you good sir.