If you're looking for manga similar to Panty Trap, you might like these titles.
Due to his sister's refusal to come home to work in the family inn, a boy is forced to cross dress by his mother. As time goes by, he comes to rather enjoy it.
Hashinomoto Maaya has wanted to marry her little brother Rintarou since she was a little girl. Rintarou seemed to feel the same way, claiming that he wanted to be together with his sister when they were all grown up. Now, after going to separate elementary and middle schools, Rintarou is about to enter Maaya's high school! Maaya is filled with excitement for her school life together with her precious brother. But when she finally sees him, she realizes the true meaning of Rin-chan's words all those years ago. He didn't want to marry his sister, he wanted to be just like her. So now, he is beginning his high school life dressed as a girl...!
A boy who wonders why his younger brother Yuuki started dressing like a girl, and decides to see what all the fun is about by trying on some of Yuuki's clothes.
Uichiro, a junior high school boy, harbors a secret he cannot share with his childhood friend, Tama-chan. He has been cross-dressing for her because she has a phobia of men.
A guy gains a younger step-brother named Aoi after his mom remarries, only to discover later that Aoi enjoys cross-dressing.
Honda, who lived that day while erasing his traces, meets a mysterious transvestite man, Himemiya. Himemiya makes Honda work at a rain fog security company. The face behind the rain fog guard is a spy who sneaks into the truth of a person and reveals the truth. It was human intelligence.
Through a series of coincidences, Yoshinori wound up having to fill in for his beautiful older sister as a model for a bridal gown. Now, he has discovered that he has a liking for cross-dressing, and that by doing so, he is learning a great deal about what it means to be a woman--and a man.