aluz and Therm have both offered good advice.
To help with the continual urge to "mate", ensure your budgie has access to lots of flight/climbing exercise.
Provide two or three swings to encourage him to keep moving and tire himself out.
Chew toys like Kabobs and other shredding toys are helpful and you should provide plenty of wood to chew--especially when he is in condition.
Reduce the number of hours of light he gets as well as the percent of protein and other foods used to bring birds into condition.