Pretty much any two lines can come after this, as long as the last word of the last line rhymes with "Blue." A few examples are...
Roses are red and violets are blue, Got kids in my basement and I'm coming for you!
Roses are red and violets are blue, Your mom is gay and so are you!
and the most common...
Roses are red and violets are blue, sugar is sweet and so are you!
Where you haven't had sex in a while and your body is not used to it and you get random boners without thinking of anything sexual
A mixed drink made from blue Hawaiian Punch and whipped cream vodka.
That blue mamba last night was the best thing I ever drank!
Sexual intercourse during which both parties have a harmonica in their mouths.
The blues traveler move may make the most god-awful sounds, but the hook will always bring that lover back.
A sub from the blue is when someone automatically likes and subscribes to your channel on Youtube.
Example 1: I thought game development wouldn't be that popular, but I got quite a few subs from the blue.
Example 2: You got a sub from the blue? Wait until you start adding more to your channel. Then the subs will start coming in like flies. It'll be more like subs from the swarm.
Blue balls, but for the bitches!
Ex: Bluegilled (blue gills) the fat one, because I thought I had a chance with the hot one