Lowkey this is sorta cute tho??? I hella support this headcanon too
I can imagine finding the new sweet spot is more or less a cute game for them, with silent laughter and little kisses here and there, and then when Hank finds the new sweet spot, then that’s when things start to get steamy
A couple places Connor has placed his sweet spot before include:
His ankle
His lower back
Palm of his hand
His hip
Like you said, Hank doesn’t back down from a challenge, so when he finds out Connor moved his sweet spot to his forehead, he just fucking goes to town stimulating that spot, and even if they looked ridiculous to someone who would see them, Connor is enjoying himself immensely, and Hank always gets turned on from hearing the noises Connor makes
Then the next day at work, Connor would get so many fucking odd looks at the big ass blue hickey on his forehead, but he and Hank aren’t even embarrassed because damn did they have a fun ass night