An Introvert's Hookup Hiccups: This Gyaru Is Head Over Heels for Me! Volume 3 by Yuishi

Lovestruck introvert Yoshin Misumai and shy gyaru Nanami Baruto are steadily growing closer, so where better to go on their next date than a steamy hot spring? Things heat up as they continue to learn more about each other (not to mention see each other in traditional Japanese clothing)! But even as their lovey-dovey antics escalate, only two weeks remain until their inevitable breakup. What more turmoil could possibly lie ahead? The couple had better buckle their seatbelts and strap down their hearts, because they’re in for a sugar-sweet ride!