Note on bundling: the kids would be placed in a bed with separate blankets and a board… and would then be sewn into the bed so as to further prevent any immoral events. As stated, it was usually done at the girl’s house (so her parents could prevent any bad things from happening) and the 2 were expected to talk all through the night.
So, if you’re thinking to yourself, “well, they’re teenagers and they’re going to figure out how to make things happen”… keep in mind that most homes of the period (up until the early 19th century) were 1-room affairs. At best, the kids would be up in the attic with the rest of their siblings, with mom and dad downstairs. So privacy wasn’t exactly widely available. Not to say it didn’t happen, but it would’ve been a challenge.