Can anyone explain to me please why Ariana Grade sings “Boy, I'm tryna meet your mama on a Sunday” but not “on Sunday” or “on Sundays”? Is there some rule I missed out? 😄

Question

Answer

A Sunday is not specific which Sunday 
On Sunday it’s specific

Answer

Hy Anya

*On Sunday is when you refer to a specific sunday/this Sunday or maybe a past Sunday.
E.g. I want to visit you on Sunday. Or I spoke to mom on Sunday.
*On a Sunday is when you refer to any Sunday.
E.g. I will visit you on a Sunday
*On Sundays is when you refer to all Sundays
E.g. I go to church on Sundays or I take the trash out on Sundays.

Hope I make sense, and you understand.