I've read you can also massage the ears to help the blood flow will help them stand. If he is teething, be prepared for the ears to go up and down, it seems to just happen during this time. If you see my avatar, none of this advice is from personal experience
I love the floppy ears, makes Kaji an eternal puppy. Plus, he was 12 months old when I go him. I figured it was a lost cause to shave his ears, massage, and tape them up at that point.