What 's that mean Dear old mom

:(
Dear Teacher ,

Now , I'm reading a book that involved with Sales closing , that mention one of activity ' Dear Old Mom' which make me stunned caused of I 've no idea about it , other close sales activity just like Ben Franklin , I can find out information in various Biz journal . But for ';Dear Old mom , I so frustrate to find out meaning of it . Do you got any Idea?
could you pleased to help me .

Best regards ,

Pachara
Thailand

[Tdol]

I think it is when the salesperson appeals to the good nature of their potential client by making touching references to their dear old mum.