2f333d6f_UX_Techniques__UX_Mastery___Technique
[What It Is] Interviewing users in the location that they use the website/app, to understand their tasks and challenges. [When To Use It] Research [How To Use It] Read Contextual Enquiry - A Primer by Gerry Gaffney for a rough guide to planning for, scheduling, conducting a contextual enquiry. [Technique] 
Contextual Enquiry
UX Techniques -UX Mastery 
Technique