hironakamura 
[@Wayneponeth](/images/2739184#comment_9894566)
Its not a catchphrase. Its a nickname you call a loved one. If AJ called Big Mac and Sugar Belle's kid Sugarcube growing up, he might have adopted it calling his own kids that nickname and so on. Kind of like naming your daughter after your grandmother or something like that.
Edit: If Applebloom had a family, she may have started calling her children Sugarcube too.
Its not a catchphrase. Its a nickname you call a loved one. If AJ called Big Mac and Sugar Belle's kid Sugarcube growing up, he might have adopted it calling his own kids that nickname and so on. Kind of like naming your daughter after your grandmother or something like that.
Edit: If Applebloom had a family, she may have started calling her children Sugarcube too.