Hello there!
I am a new Yorkie owner, got her 2 months ago when she was 4 months. The breeder was taping her ear, but didn't tell me about it because the ears were standing a few days before I took her home.
However, a few days after arriving at my house, the left ear started to droop more and more. I thought she looked so cute!! But I was worried that other people might not appreciate it as much as me and treat her less, er, nicely just because she's not "perfect", so I went on to learn how to tape. A week, two passed by, after several tapes, still droops when I take it off. Went on to research some more, and the next thing I did was shave the ears. Well not really have, more like cut it really short almost to the skin because I don't have a shaver. Oh, the life of a single girl!
Anyways, it stood up or shall I say stopped drooping immediately!
The hair's grown quite a bit since then, and 2 days ago the left ear was drooping again, so I cut the hair again. Stands up no problem. I never put the tape anymore. Not because i am against it, but because Mocha is a rambunctious girl and it's very difficult to clean the ears. Besides, if it stands just with less hair, why tape?
If you really want them both to stand, I think it best if you just try shave the hair first. In my experience taping can be very difficult if your baby won't stay still. But it's up to you. In my opinion, hair will grow back
I think Mocha is perfect any way, but you can see in my avatar how smart she looks with both her ears standing up
For me, shaves and massages is enough, thank the puppy gods.