No matter how gay the situation looks, it will not be gay as long as you say "no diddy". It is a phrase that replaces the traditional "no homo" term which has been used for a very long time.
This term has gained a lot of recognition after Diddy and Bad Boy Records have been trending after almost 15 years in the music industry.
John: Yo Pete, Jessica's husband is kinda hot. No Diddy!
Pete: Well said John, she knows ball when it comes to choosing the right life partner.