http://www.hkmj.org/abstracts/v20n4/351.e3.htm

Firstly, gentle air insufflation may cause evertion of inverted diverticula. In some cases, a jet of water may be used to flatten the lesion.² Secondly, probing the lesion gently with a biopsy forceps will show a soft lesion with easy indentation. Interestingly, it was recently suggested that the presence of Aurora rings can support the diagnosis of an ICD.³

2．Cappell MS. The water jet deformation sign: a novel provocative colonoscopic maneuver to help diagnose an inverted colonic diverticulum. South Med J 2009;102:295-8. 

3. Share MD, Avila A, Dry SM, Share EJ. Aurora rings: a novel endoscopic finding to distinguish inverted colonic diverticula from colon polyps. Gastointest Endosc 2013;77:308-12