Didi ah.

A phrase written, or said softly or in a loud manner with a certain teasing nature, which can be used as an expression of joy, surprise, disappointment, fear, as a greeting, etc. It is also used as a filler phrase, or substitute in cases where the speaker does not know how to address a certain situation. This phase is most commonly used in online gaming as a kind of expression for an unexpected occurrence depending on it's novelty or manner of execution.

'Didi ah.' can be used in different situations.

In online MOBAs:
When someone missed a crucial skillshot you say "Didi ah!"

When someone chases you down and your teammate was able to protect you accordingly you say "Didi ah!"

When you meet that one person you always play games with you say "Didi ah!"

*Didi ah can also be used as a playful banter, i.e. when your teammate misses his skillshots you say "Didi ah!" With a hint of tease (must be said multiple times for a minimum couple of months before said 'hint of tease' manner can be excecuted in an acceptable manner.