#NationalSendANudeDay is a made-up holiday used to trick people (can be your significant other, a friend or a random person) into sending you naked pictures of them.
Since it is an unofficial holiday, its recurring date is not set in stone, but usually it is held on the 5th October as it was first posted on the social media website Twitter on that day.
The hashtag can be used to make fun of various other holidays on Twitter.
Originates from the social media website Twitter, where a user used the hashtag: #NationalSendANudeDay in his post for the first time on 5th October 2012.
At first, the hashtag was not well received and was used sparingly, until on 22nd April 2014. A picture of a naked woman was posted on the social media website Twitter using the phrase.
It has spread very quickly due to the nature of these images (nude mirror selfies) as the internet loves browsing for adult entertainment and anything related, especially if the pictures are about people who “expose” themselves.
The hashtag/phrase is mainly used on the website it was created on, Twitter, but can be seen on other message boards like 4chan and Reddit.