I could never wear this shirt because people could see right down it.
I couldn't wear a tank top under it either, because my tank tops are loose on me, so the shirt would just drag the top of the tank top down.
I read somewhere that elastics could help the neckline go up, but I didn't have any elastics
So I improvised :D
Divide the front of your neckline into eight equal parts.
Cut a slit on the red lines/blobs.
Don't cut all eight parts like me. I messed it up :x
Get two pieces of ribbon (one longer than the other) and tie it through a bobby pin
Using the bobby pin like a needle, string it through one end and let it come out on the hole you made on the neckline. Do the same on the other end. Sew the ribbon onto the ends of the shirt so they stay in place.
Tighten the ribbon to your liking, and the neckline should go up :D