I think it happens in 'Konosuba: God's Blessing on This Wonderful World!' But the details might vary depending on how you interpret their relationship development.
As a fan of online literature, I don't have any detailed information about the sleeping habits of Northeasterners. However, from some novels and articles, one could understand that different cultures and regions had different habits and ways of life.
In some novels, there might be a family sleeping together in the plot of the Northeastern women selling large brick beds. However, this did not mean that all Northeasterners would do the same. In addition, people in different cultures and regions have different sleeping habits. For example, some people may like to sleep alone, while others may like to sleep with family or friends.
Therefore, I am unable to provide an accurate answer. If you have any other questions about the sleeping habits of Northeasterners, I will try my best to answer them.
In the manga, Mafuyu and Uenoyama do not sleep together. The focus of their story is on emotional connection and personal growth rather than physical intimacy.
In the comics, Wanda and Pietro did not sleep together. Their relationship was more focused on their superhero activities and family dynamics rather than anything of that nature.