Hi Angrysqueak, It roughly means "罪恶的快感", or "内疚并喜悦的矛盾心理". There are also another internet slang "恶趣味" which might fit for such phrase. But the use of "恶趣味" is rather flexible. The reader will have to rely on the certain context to interpret it as "拿不上台的爱好". If you have any questions regarding the above terms feel free to ask.

Hi! There is no single word in Chinese exactly same as “guilty pleasure” . So if we want to translate its meaning, we can only use two words to describe it according to the Situation. Such as 内疚的快乐；有负罪感的快乐；我觉得“又负罪又快乐”；罪恶的快感,etc. Sometimes you just can not translate word by word from one language to another because their different language systems and culture differences.