“Put a potato in your swim trunks to attract more women” (joke)

A joke has it that a luckless young man asks a lifeguard for some help with women. The lifeguard suggests that he put a potato in his swim trunks. However, the young man returns later and tells the lifeguard that women just laughed at him when he did that. “The potato goes in FRONT,” the lifeguard replies. 
 
That is, the potato in the front of his swimsuit was supposed to improve his male sexual package, but instead, the potato in the back told others that his swimsuit was full of shit.
 
The potato joke has been cited in print since at least 1983.
   
       
Google Groups: net.jokes
Dirty Aggie Joke - (nf)
James Fontenot
7/28/83
#N:hp-pcd:5500032:000:455
hp-pcd!jrf   Jul 27 15:36:00 1983
It seems there was this aggie who, while at the beach, noticed all the tastie ladies were drooling over the lifeguard.  When the aggie confidentially asked for his secret, the lifeguard whispered,“Put a potato in your pants”.
 
The next day the aggie came to the beach with potato in place - but with no discernable effect upon the ladies.  He couldn’t figure out what the problem was, so he asked the lifeguard,“Put it in front”, replied the lifeguard.
     
Google Books
National Lampoon
Volume 2, Issues 66-77
1984
Pg. 12:
EXAMPLE 2: Charles had no luck with women. One day at the beach, he spotted a friend who was always surrounded by sexy girls and asked for advice.
 
“All you gotta do, Chucky-boy, is put a potato in your trunks. It works every time.”
 
Charles thanked him and did what he was told. The next day he ran into his friend, who asked how he had made out.
 
“It was awful!” cried Charles. “Everybody pointed their finger at me and laughed!”
 
“You’re supposed to put the potato in front, asshole.”
 
Google Groups: eunet.jokes
BROLOID potato joke
.(JavaScript must be enabled to view this email address)
2/14/90
During summer holidays, a guy comes to the beach with a friend of his.
”- Hey, look at this girl… She’s smiling to you… You’re so lucky with women. I don’t understand how you do…
- Just be yourself. But if you really want to impress women on the beach, put a potato in your swimsuit, and they will all drool at you…
- I will try.”
Two days later, the guy meets his friend on the beach :
”- Hey ! Tell me. I did as you said, I put a potato in my swimsuit, but women are not interested at all : they all laugh at me !!!
- Because you should have put the potato in the front of your swimsuit, not in the back !!!!” 
 
Google Groups: alt.tasteless.jokes
Beach Joke
Modemac
6/13/96
[An old joke and you’ve probably heard it before.]
A textbook nerd is at the beach one day, baring his chest and showing off his pale, shrunken chest, and of course all the girls are laughing at him and drooling over the weight-lifting hunks.  So in desperation the kid goes to the lifeguard and asks, “How can I do something to get these girls interested in me?  What can I do to show off?”  The lifeguard takes pity on this poor guy, with his puny muscles and baggy trunks and lanky hair, and finally he says, “Tell you what - why don’t you take a potato and stick it down your swim trunks.  That way the girls will think you’ve got something really big and hard down there, and they’ll want you.”  So the nerd decides to give it a try.  He struts around the beach with a potato in his shorts, and all the girls give him weird, disgusting looks and tell him to get the hell out of there.  The nerd can’t understand what’s going on, so he goes back to the lifeguard and asks, “What am I doing wrong? You said they’d like me if I put a potato in my shorts!”  Without even batting an eye, the lifeguard says, “You gotta put the potato in the FRONT, kid!”
 
Reddit—Jokes
Posted by u/zenith2nadir July 13, 2015
A man goes to the beach…
...and he sets himself up to show off his new beach bod. A few women glance his way, but none strike up a conversation. He looks a little ways down the beach to see lots of women around an older guy who is nowhere near as chiseled as him.
 
As the crowd disperses, the man approaches his competition and asks the older man what his secret is.
 
“Sure, I’ll tell you! It’s real easy. First thing I do before stepping out onto the beach is put a potato in my Speedo. It’s a real eye catcher, if you know what I mean!”
 
Seeing the older man’s success, he decides to give it a try. The next morning he stops at the market and buys the biggest potato he could find and heads off to the beach. He sets himself up like the day before and puts the potato in his Speedo, but now even less women are glancing at him. Some are even making comments under their breath.
 
Confused, the man finds the older man from the day before and asks what gives.
 
“I did it just like you said, stuffed the potato in my Speedo and everything!”
 
The older man shakes his head in disgust.
 
“You idiot! You’re supposed to put the potato in the FRONT!”
       
Reddit—Jokes
Posted by u/Fozzieboy February 26, 2017
Boy complains to his father:
Boy: You told me to put a potato in my swimming trunks! You said it would impress the girls at the pool! But you forgot to mention one thing!
Father: Really, what?
Boy: That the potato should go in the front.
 
Reddit—Jokes
Posted by u/man5world July 30, 2018
Potato in your swimming trunks
Boy complains to his father: You told me to put a potato in my swimming trunks! You said it would impress the girls at the pool! But you forgot to mention one thing!
Father: Really, what?
Boy: That the potato should go in the front.
 
Reddit—Dadjokes
Posted by u/Funny-Promise956 July 30, 2020
My dad once told me that if I put a potato in my swim trunks, I would attract more women…
He forgot to tell me to put the potato in the front
COMMENTS
chilldabpanda
Did he specify “not mashed”?
My Dad didn’t.