So, basically...
A prostitute tried to run away from one of Rogi's brothels and the uke beat up the men trying to bring her back, so he basically helped her escape. That prostitute, as the manga says, had lots of implants and plastic surgery made on her so lots of Rogi's money was spent, so when she ran away the uke wanted to make up to him, but he asked for 2 million dollars, something that the uke didn't have on him to pay.
Rogi wanted to make the uke ask for his father's help, his true target, but the uke refused to ask his dad for money so Rogi wanted the seme as a subistitute to gain the 2 million back, but the uke didn't want to betray him like that (even more so because of the seme's past of being sexually abused) so he instead offered his own body to Rogi (that also agreed because he thought that having sexual relations with the uke could bring his father to him)
I can't stop laughing at that last panel. Btw i barely understand on what purpose the uke walk to rogi. To pay what? I read all but idgi.