哥很纯也很暧昧姐不纯也不暧昧
[gē hĕn chún yĕ hĕn ài mèi jiĕ bù chún yĕ bù ài mèi]
A somewhat contradictory statement that means while he claims himself to be innocent yet flirtatious, the other (sister) isn't as innocent but doesn't act coy. The contrast might express his humorous perspective of both personalities, with a hint of self-mockery.