Lyric discussion by musichead101 

Cover art for Sippy Cup lyrics by Melanie Martinez

What I think is

Just because you want me to think one way about something, doesn't mean I will

"Blood still stains when the sheets are washed; Sex don't sleep when the lights are off"

I really think these lines are saying just we aren't stupid and you aren't sneaky.

"He's still dead when you're done with the bottle; Of course it's a course it's a corpse that you keep in the cradle":

No matter how you disguise or cover up the situation to sugar coat what it really is, people can always tell.

"Kids are still depressed when you dress them up; Syrup is still syrup in a Sippy Cup"

The gist of the song (to me) is basically you aren't being as sneaky as you think you are

My Interpretation