When you're playing League of Legends as Tahm Kench and you bust out the big guns to go swallow up the enemy team's carrying player before spitting him out into the middle of your team for you all to dog pile onto like they're delicious BBQ chicken wings.
Also relevant if everyone is dead, you're 1v1'ing a fed Nasus and you gotta kill that fucker before he Q-slam 1-shot's your nexus.
First quoted by BrickyOrchid8 in his Story Time video 'Unbench the Kench'.
From 绷不住了, bēng bù zhùle, literally "unable to stretch anymore". Means to be pent up and unable to hold back (such as in sexual urges, laughter, or anger). Basically means, "I can't help it".