北冥西柚北冥柠檬
[bĕi míng xī yòu bĕi míng níng méng]
This seems inspired from Zhuangzi's essay - Northern Darkness ('北冥'). 'Pomelo' and 'lemon' could refer to their tastes or the owner wants his/her identity symbolized by these fruit types. Maybe this person sees oneself as sour but refreshing.