Here is a great video showing various options of the Judo technique Sumi Gaeshi. Similar to Tomoe Nage but instead of placing the bottom of your foot on your opponents hip flexor, you will place your instep on their inner thigh. Be sure to maintain grips all the way through enabling you to use your opponents momentum to take mount position. Sumi Gaeshi is one of my go-to techniques against an opponent with a low base, especially in a push/pull situation. As soon as I feel the slightest push, I go!