Piped text from a drag and drop response

So this will depend a bit on how your drag & drop question is set up, and what exactly you want out of your piped text. With a drag & drop question, you can pipe text based on selected choices, or an item's rank within the group... Does your piped text need to reference items dropped into a specific group, or any group, or...?

In any case, I think the easiest way to do piped text is to let Qualtrics do it for you. If you are piping text into a question, then click on "piped text" when you are editing your question. If you are piping text into an answer choice, then click on the small blue arrow next to the answer choice. Then click on "Insert piped text." Choose to pipe text from a "Survey Question" and then select the question that you're interested in. Here's a screenshot of what that process looks like and what the built-in options are for a drag & drop question.

Here are some examples of what you'll get.
Item 1 Description: this basically just carries forward the choice text for a given item, and will display regardless of if that item is sorted or not. Your piped text will look like:

${q://QID1/ChoiceDescription/1}

Selected Choices: this will give you ALL items from your drag & drop that were selected, no matter which group(s) they were sorted into. Your piped text will look like:

${q://QID1/ChoiceGroup/SelectedChoices}

Item 1 Rank: the rank of the first item in the drag & drop question, in whatever group it landed in. Your piped text will look like:

${q://QID1/ChoiceNumericEntryValue/Rank/1}

In each of these examples, "Item 1" would correspond to an actual answer choice in your drag & drop question. QID1 is the internal ID for the drag & drop question. This will likely be different for your survey, depending where your drag & drop question is.