The LoveTrainer's essentially a pair of sporty headphones with an attached heart-rate monitor that fixes to your earlobe. This dictates the "sensual voice narration, dynamic rhythm and music" pumped into you during rumpy-pumpy.
For example, if you're going at it hard and fast then you'll hear fast-paced music and positive, driving narration, such as - and this is really what it says - "You are making love at a very good pace." But if you're not up to the job then the music's pace will slow and you'll hear messages like: "Your stamina will be evaluated." If you get too slow, you'll likely hear: "Please confirm the heart-rate sensor."
LoveTrainer's also got a built-in safety system. If you try too hard then you'll be told that "making love a bit more gentler would be perfect". Eventually, as she trots off to the bathroom and you reach for the tissues, the LoveTrainer will say: "Well done! Let's make love more regularly."
The gadget will never be a wasted investment, either. Because even if you and your partner grow tired of nocturnal nookie, the cans feature an audio input so you can use them like regular headphones.