Ok, you’re not actually wrestling. You’re sitting opposite your teen, partner or friend using your body weight as resistance, not letting him/her move your legs.
-Sit face to face with your legs on the inside, your partner’s legs on the outside. At the same time, you push out, they squeeze in. See if you can keep constant resistance so your legs don’t move. If you are feeling strong, lift your arms above your head and lean back slightly (you don’t want to feel pain in your lower back while doing this, or anything!) Feel your abs engage? Feel your outer thighs as you push out? Your inner thighs as you squeeze in? Good. Are you laughing? Probably.
-Now switch. You have your legs on the outside, your partner’s on the inside. You squeeze in, they push out. Lift your arms above your head and slightly lean back. Keep resisting until your legs shake and then hold it some more.
-Repeat above in both positions, but this time with straight legs rather than slightly bent. By the end of four rounds, you should feel new muscles in your inner and outer thighs, as well as your glutes that you haven’t felt before. Plus your abs will be exhausted from leaning back, depending on how competitive you are.
-Next time you play, try the same as above but change it slightly. Rather than keeping your legs in one static position, keep constant resistance but let your legs move in or out. Still lean back to engage your abs. It’s hard to be super strong when laughing; nevertheless keep laughing. It’s funny, and very effective too.