This is a closed guard break technique where tori begins to stand from their knees, prompting uke to pull tori with their collar grip or collar tie.
As uke pulls on tori, it is exceedingly difficult for them to both pull tori’s head AND focus on clamping their legs tightly. At the moment uke begins to pull, tori can push downwards on uke’s thigh with their forearm, breaking uke’s closed guard open.