Jack grins slowly. No point in disputing the compliment when it's so obviously true. Besides, this is a beauty he's worked on. Okay, sheer physical beauty he was given, but the openness, the ease of movement, the knowledge of how he looks from any given angle and making sure Ianto has the best angle possible - that has taken decades of experimentation to perfect.
Keeping his eyes on Ianto, he reluctantly lets go of his cock before he gets too far along and instead pours out more lube into his hand, generously slicking his fingers. Easily, he kneels up and trails one finger down between his cheeks to his hole, moaning softly as he pushes it in. His breath gets a little faster, a little shallower as he begins to work it in and out, working the muscles, teasing them into relaxation so he can push the second finger in to work alongside it.