I'm not a fan of using honorifics in a text in another language than Japanese, but I did it for this fanfic.
At Mamoru's apartment, Usaku joins him in his bed. Why does he feel nervous? It's not the first time they sleep together. Mamoru feels his nervousness.
"Relax. We're both in this together. Everything will be fine." He said to reassure him.
Usaku knows it well and, nevertheless, his flesh can't help shaking.
"I know, Mamo-kun, but I keep shaking."
Mamoru takes Usaku's hand and caresses his arm gently. Usaku is startled.
"Sorry, I—!"
"That's okay." Mamoru said as he kissed his hand. "We have plenty of time ahead of us."
Mamoru is gallant with Usaku. His hands take the time to caress his arms and his belly, to relax his skin, before touching his more intimate parts. When Mamoru pinches his nipples, Usaku moans softly. When he kisses his neck, Usaku shivers with pleasure. When he gives a hand job on his cock, Usaku orgasms quickly and his nervousness is gone.
"Ohhh~ Mamo-kun! I want to make you moan, too."
"You can. What do you have in mind?"
"A blow job."
Mamoru nods and Usaku puts his mouth, so soft, on the cap of Mamoru's cock. He kisses it before sucking it, then goes deeper and deeper. The cock of his love being far in his mouth. Mamoru moans and orgasms. His cock starts to harden.
Mamoru continues to caress the tail of his Usaku. The lovers moan more and more loudly. Their cocks ejaculate at the same time. However, Usaku withdrew before the ejaculation and that disappoints Mamoru.
"Sorry, Mamo-kun. I don't like the semen’s taste in my mouth."
"I know, but you can do something else instead."
"Oh really, what?"
"Come in through my back door."
"With pleasure!"
Mamoru changes his position so that his buttocks are clearly visible to his love. Usaku teases his entrance with his cock before penetrating him gently.
"Ahhh~ Usaku, YES!"
"Mamo-kun."
"Go ahead and fuck me, my love. Come inside me."
Usaku grants Mamoru's wish. Then, Mamoru does the same thing with Usaku's asshole, then the lovers rest. Usaku tries to sleep but he can't, with the sperm traces in the bed. So Mamoru goes to change the sheets. Meanwhile, Usaku goes to the bathroom to clean himself.
"You should do the same." He advises Mamoru.
"Okay."
Usaku returns in the bed and Mamoru, freshly cleaned, joins him. They hug each other and fall asleep quickly.