Single mothers and married mothers looking to upgrade their husbands will often take their daughters out to socialize. The mother uses her daughter’s presence to attract men while blocking any man who shows more interest in the daughter than in her.
 
Man: “Hey, you two look like sisters.”
 
That kind of line makes the mother tingle inside.
 
Just like a fat, unattractive friend will chase off men interested in her better-looking friend, the mother will run interference for herself. In these situations, a second man is often needed to take one for the team by charming the mother or the chubby friend so the other man can pursue his target.