The idiom 'your ears must be burning' can be said to somebody who appears during or just after a conversation or discussion in which they are the main topic, or even just mentioned. In that context, it is similar to the phrase 'speak of the devil.' The expression can be changed to 'my ears are burning' when you want to express the feeling that somebody is talking about you.
As you can see from our video, it can be used informally in both a social and professional context, and after saying or hearing something good or bad. For example, if you are talking about someone, or hear yourself being talked about in a positive or neutral manner, the expression can be used humorously, especially among friends. However, in a negative context, say if you are gossiping or being gossiped about, it becomes something unkind which can cause discomfort and embarrassment, similar to the term 'go behind somebody's back.'