"Fuck Their Shit Up". Made famous by 'A Voice For Men' website.
Most frequently applied as a response to feminist ideology and practices, but can be used in any context.
Example 1. Feminists want to limit the number of males gaining entry into university, we need to actively FTSU.
Example 2. The skinheads are trying to preach hatred of ethnic minorities, let's FTSU.
Example 3. There is a nest of termites trying to eat away my house, I need to FTSU, and quick!