This website contains age-restricted materials including nudity and explicit depictions of sexual activity.
By entering, you affirm that you are at least 18 years of age or the age of majority in the jurisdiction you are accessing the website from and you consent to viewing sexually explicit content.
Good luck at the border.
Unless things have changed significantly at the border in the past few years, there’s no process to leave the US. It’s just the Canadian border guard checking things as you enter their country.
Of course, if the GOP decides to fully enact Operation: Handmaid’s Tale, then that could change.