Yuri x Kocho!

Saki Ogura, a lone-wolf delinquent, is determined to rise to the top of the high school. But her plans are disrupted when she's approached by the class's most popular girl, Yuka Oguri. Though Saki finds Yuka annoying at first, a strange turn of events leads to Yuka discovering Saki's secret weakness—she's extremely ticklish!?

(Source: Kadokawa, translated)