I have a 3 month month old Decker RT.
As I recall when reading the breed standard online it says the DRT ears 
should be up by 3 months and I think I also read (not sure where) to tape them if they aren't.  
The breeder told me it can take up to 6 months so I'm not sure what to think not being familiar with this breed.
Having a lot of experience in the past with cropped Great Dane ears I glued a foam pad in her ear and tape them up yesterday but today she was crying if I touched her ears do I took the stuff out of her ears and the skin was irritated and red.
I cleaned them out and put some antibiotic ointment in her ears and didn't re-do them. 
She's fine but now I'm wondering what to do about the up or down ear situation.
Both her parents have button ears. 
I assume its genetic but was hoping to encourage her ears to go up.
Any advise appreciated.

Well I would prefer Shelby's ears up but not going to make a big issue out of it.
Would still like to hear from thiose who have taped ears to make a button ear erect.

Couldn't figure out how to post pics in the message so here's a link to a few pics of my new DRT
http://www.fototime.com/inv/383FEEB5AB553CA

Welcome to the group.  Your little puppy (little for awhile, anyway--haha) is adorable!  I have never heard of anyone taping a rattie's ears to make them stand.  Ears are acceptable either buttoned or erect.  I have 2 ratties and Lucy has buttoned ears, and Bo has erect ears.  They are both close to 3 years old now, and that's just the way their ears are.  I know that ears are taped to encourage standing on dobies, danes, boxers, schnauzers, etc AFTER surgically cropping (I also have a doberman with cropped ears) but I just didnt think that anyone actually taped ears that had not been cropped to make them stand on any breed.  Of course, I sure dont know all there is to know about ears, dogs, or anything else for that matter, so maybe it's a common practice, but I have never heard of it.

Again, welcome to the site!  Hope to see more of your little fur-baby!

I can't remember where I read about taping DRT ears...maybe on the breed registry website or on a breeders website. 
I had Great Danes for many years and don't feel cropping or taping their ears was "mean".
None of them were traumatized by the process. 
Is tail docking mean? 
Mean is subjective.

Now that is a great looking pup!

And he is a pup... the ears may go up and maybe not.  IMHO, RT ears are a bit disproportionate to their bodies, so I like the buttoned down look more.  Murphy's ears are buttoned, though they raise (mostly) when he's alert.   It's accepted in the breed for the ears to be either way.  I'd suggest you just let the genetics decide how his ears should go, and just enjoy him.

my dobie has natural ears...we had another dobie (her great-uncle) whose ears were butchered...they took too much of the ear off, and the ears never stood up...I don't think there was enough of the ear left to stand up.  poor guy.  so when we got Rosie, we decided to not have her's done, although she does have a docked tail.

just because you can't imagine a dobie with natural ears, here's Rosie, my red dobie

Your Shelby is absolutely beautiful! As far as cropping, docking, taping, there will always be very strong opinions on both sides. My opinion is that none of it is necessary unless you are showing and you NEED to follow a standard. If this is just a family pet than there is no neccesity. If you do NEED to or simply WANT to I feel that it should be done by a professional. Have you checked with your vet?