夏天的爱人是西瓜西瓜的恋人是暑假
[xià tiān de ài rén shì xī guā xī guā de liàn rén shì shŭ jiă]
A playful way of saying that in summer one's 'lover' is a watermelon, while for watermelons, 'their lover' is the summer vacation. It captures a whimsical association with summertime pleasures.