While these phrases are common in "tongkrongan" (hangout) circles or specific online communities, they are considered highly informal suggestive
It mimics a deceptive promise made during a sexual encounter. gesek dulu janji cuma kepalanya doang eh mentok babe
Use it as a cheeky, "edgy" caption for photos that show a surprising or "full-on" result after a modest start. While these phrases are common in "tongkrongan" (hangout)