Happy Death Day (2017)

A sorority girl named Tree (short for Theresa, played by Jessica Rothe) wakes up in a stranger's dorm room, and goes about her college day - that is, until she gets murdered and promptly wakes back up in said guy's dorm room, only to start the full day over again. Eventually, Tree realizes that she's on a time loop that won't end until she identifies who the killer is and kills them first. That happens over and over again, inflicting more and more damage on her body. Speaking of, we see in her panties post-dorm hookup, plus a hint of buttcrack when she walks around campus naked. Rachel Matthews dons a sports bra as her sorority sister to boot! This horror take on Groundhog Day will have you peaking out of your pants!