put lead in one's pencil

put lead in (one's) pencil

To increase, enhance, or restore a man's sexual ability or vigor. You should try bungie-jumping at least once in your life—it will put lead in your pencil! The only real way to put lead in your pencil is to eat well, exercise regularly, and have self-confidence.
See also: lead, pencil, put

put lead in one's pencil

Enhance or restore sexual vigor, as in Try one of these hot peppers; that'll put lead in your pencil. This phrase, a euphemism for causing an erection, is considered far more vulgar than the contemporary synonym put hair on one's chest, alluding to a secondary male sex characteristic. [Colloquial; c. 1900]
See also: lead, pencil, put