It's a magical power all semes have where the uke's clothes vanish against all laws of logic and reason!
or the mangaka got a little lazy.
ahahahah!!!!! this is like those moments when the seme has an orgasm and in the next second he is still hard to penetrate the uke and have another orgasm together... pure magical power..
One moment he gets tied up with his entire suit on and the next moment he's still tied up but the jacket is gone. http://www.mangago.me/read-manga/omae_de_nakya_dame_mitai/mh/c005/22/