Grow more, to the point you can destroy entire cities at once

There's barely any need for that now. Your little lovemaking session was enough to elongate the both of you twenty miles tall. With your three-mile long feet, many a city looks to you like small puddles.

Sophie: "Hey, I've got a neat idea! Come on now, I need you over here."

Steve: "Okay."

Steven follows you a over to another city. You're not exactly sure which city this is, but it's barely big enough for you to see. You motion Steven over to it.

Sophie: "Careful now. Don't wanna ruin the fun. Get down on all fours and point your erection at that."

Steven: "Ho-hoo... alright!"

You see that all the roads in the city are jam-packed with cars trying desperately to evacuate.

Sophie:"Hey! That's not allowed."

You draw a single finger along the ground around the city, forming a full circle. The city is now surrounded by a 300-foot deep impassable gorge. This has effectively cut off every single road at once, making escape by foot or car impossible.

Sophie: "Steven, how's it coming along?"

Steven is still in the process of masturbating furiously. It's a bit difficult, seeing as how this is his third time within an hour.

Sophie: "NNNGH! I just can't get it to launch!"

Sophie: "Aww, poor you. Let me help out!"

You scoop up another nearby city in your hand.

Sophie: "I've got here another city! Ooh, looks kinda metropolitan, probably really high population density..."

Steven: "Oh no! Whatever would I do if something would happen to all those people!"

Sophie: "Don't worry, I have them safely on my- WHOOOPSIE!"

You slather the city against his testicles, rending everything between your hand and his scortum into paste.

Sophie: "OH DEARY ME! Crushed, killed and destroyed, all of it! Oh boo-hoo. That was hundreds of thousands of lives snuffed out in an instant! How's that make you feel?"

Steven: "H-h-huh... Aww, fuck yeah..."

Sophie: "Do I need to make another 'accident' happen? Or would you like some hands-on help with that?"

Steven: "H-HAAAAH!"

The heavens open up for this innocent little city, as billions of tons of pungent goo drown everything in its wake. The mere **** of his ejaculation was able to break deep into the bedrock, and the devastation at the impact site is more total than a nuclear bomb.

Sophie: "That's a good boy..."

Sophie: "F-... fuck that was good. But I need a rest. Now it's your turn!"

Sophie: "Alright."

The problem is, you're a woman and can't really ejaculate.