Love Round!!, Ashita wa Docchi da! Recommendations
The uke in both manga faces the same problem - due to his frail and feminine appearance, he develops a certain amount of self doubt/insecurity. And in order to make a change in his appearance and attitude, he decides to follow the footsteps of a more "manly" guy. Bonus: both the uke are NOT useless - in fact, they have a short temper and are quick to use their fists.