This flag, created from existing flags and symbols, is designed to combine symbols related to transgender, bisexual, and BDSM subcultures, in order to create a flag to represent those who identify with them.
The striped background of the flag, in the pattern blue-pink-white-pink-blue, comes from the transgender pride flag created by Monica Helms in 1999. The blue represents male aspects, as the traditional color used for baby boys. The pink, likewise, represents female aspects. The white stripe is for those who are intersex, transitioning, or consider themselves having a neutral or undefined gender.
In the center of the flag is the triskelion, a common symbol associated with BDSM, which appears on BDSM pride flags such as the BDSM rights flag by Tanos. The sections of the triskelion are colored pink, blue, and purple, echoing the colors of the bisexual pride flag (the shades of the colors have been altered to match the rest of the flag). Pink and blue can be seen to stand respectively for either attraction to females and males, or for attraction to same- and opposite-sexed people, while the purple represents the possibility for attraction anywhere within the gender spectrum.

The flag's aspect ratio is represented here at the common 1:2 ratio, but this should not necessarily indicate the author's desire it be fixed at this ratio.
Own work based on: Transgender Pride flag.svg, File:BDSM-rights-flag-Tanos.svg
Mnmazur