Shepard was sitting on the couch of his private quarters, wondering what Tali said she wanted to show him, when she messaged him earlier.
His thoughts were interupted when he heard the door to his washroom opening; he didn't know she was in there. He looked over, and saw Tali walking out of it and coming around his desk. Something was different; she was not in her suit. All she was wearing were a pair of black, lace panties and a matching bra.
"So um... I read that it's common among humans for females to wear... undergarments... like these. For, you know, males that they're in a relationship with..." Tali said, nervously holding her hands together as she stood before Shepard.
All Shepard could do was stare, slack-jawed and happily, at the beautiful, stunning sight before him. He was obviously pleased with what he was looking at, which quickly became apparent to Tali; she then began to approach him.