2 sentences

1. 你的左臀上有一处瘀青。

   nǐ de zuǒ tún shàng yǒu yī chù yū​qīng.

   There's a bruise on your left buttock.

   Source: OpenSubtitles

2. 他在搏斗中不幸被毒箭射中了右臀。

   tā zài bó​dòu zhōng bù​xìng bèi dú​jiàn shè​zhòng le yòu tún.

   During the fight, he was unfortunately struck in the right buttock by a poisoned arrow.

   Source: Dong Chinese Dictionary