If Leah had known that the topic of tape would be so intriguing to him then she might have brought it up earlier. But really, it was just tape so that her dress wouldn't slip and slide and give everyone a free show! She was really just being modest, obviously.
"Hm? Oh, yes," she said after she realised what he was referring to. "It's so that my dress won't slip around or anything. Why.. can you see it?" she asked, now subconsciously looking down to make sure that nothing was peaking out.