Do not push the knee with your hands โ that straight arm is the spinning-armbar invitation.
Frame at the ankle-side hip with your elbow tight; shrimp INTO them, under the riding knee.
Catch their posting leg with your knees as you slide under โ half guard is the exit ramp.
Where it goes wrong
Pushing the knee across with both hands and getting armbarred exactly as designed.
How opponents counter it
Float on the reaction and switch to the far side
Baseball bat grips as their elbow lifts
Is the Knee on Belly Escape legal in competition?
Legal in all major rulesets at all levels (IBJJF, ADCC, sub-only). Rules change โ always confirm against the current official rulebook for your event.