Anthony Weiner -- Offered Lessons On Proper Penis Pic Etiquette

Anthony Weiner's odds of becoming the next NYC mayor are shrinking faster than his schlong on ice ... but not to worry ... he's being offered lessons on how to sext, without destroying his career.

Since the sexting scandal broke last week Weiner has dropped several points in the polls ... been publicly scolded on national TV and as of Sunday, his campaign manager up and quit.

Not all hope is lost ... Trent Silver, the CMO of Silver Visibility -- a media marketing company -- fired off a letter to Weiner offering the co's services to get his campaign back on track with a "dose of PR Viagra."

Specifically in the letter, SV says their experts "will teach [Weiner] the proper way to use social media so [he] won't get caught with his pants down."

SV suggests using Snapchat -- a photo sharing app where pictures destroy themselves -- so that Weiner's "dicktures disappear in six seconds rather than [his] political career." It's a great app.

SV also says they can help train him on the "finer points of sound bytes" ... which is code for, please stop sticking your foot in your mouth.