Abu Hurayrah narrated: ‘The Prophet said: When you go to relieve yourselves, do not face the qiblah or turn your back to it’ (which is why Muslims are often advised to go east or west).’
He also said: ‘Do not use bones or dung for cleaning, for they are provision for your brothers among the jinn.’
Sahih Muslim
The jinn delegation requested that bones not be used because they eat from them. The respect shown towards the qiblah extends beyond relieving oneself, as Muslims are also forbidden from spitting in that direction. For another story involving the jinn, you can read about the Ifrit who was to be tied in the mosque.
