A bit more about the word "кушать".

There's a lot of softness and even some kind of intimacy in this word. It's usually used with diminutive-hypocoristic suffixes -чк- (i.e. "кушать курочку", "скушать яблочко". Such phrases are usually used in mother-child or men-women relationships that mimic mother-child.

If you can express yourself properly with diminutive-hypocoristic suffixes - you'd easily find proper way to use the word "кушать". If not - you should consider avoiding it.