Drop dime means to rat someone out, or reveal information, in any situation. It derived from late 1960's and 70's South, where there were 33 fires a day at one point, and crime was the highest it ever was. Thus, many people would rat to save thier own ass, and they'd use a dime because that's what it cost.
Yo man, somebody dropped dime on me. My probation officer know about my bid'ness.
dime out; to rat out somebody
"I pity the sorry-ass s.o.b. who dropped dime on Luger."
Verb-1. To defecate. Can also be shortened to "dimes". 2. The need to defecate in a hurry. Usually there is a small window from when this phrase is uttered to the act of defecating.
Mark-"I really need to drop dimes!"
Anne-"Don't worry, I'm pulling into the nearest rest area."
Mark-"I hope it's close...dimes, honey, dimes!"