He should be gone. He should have left, should have gone to tell Sirius goodbye, though not tell him the extent of it - but instead he's here, clutching at the front of Remus' shirt and sobbing as he crawls into his lap. He doesn't think he believes that Remus really trusts him, but he can pretend for this. Needs to pretend for this.

He doesn't say anything for a very long time, breathing shakily. Nothing can ever be the same, but this moment will exist in perpetuity. It has to be enough.

Hopefully Remus won't notice that he has his wand in hand as he clutches at Remus' chest, or that the inaudible murmur actually means something. In fact, he tucks it away again before Remus can notice and finally smiles, just a little, even though it doesn't reach his eyes.

"Thank you," he murmurs, "and I'm sorry. For not being trustworthy enough." A breath as he lets go and stands, one hand smoothing over Remus' hair as he kisses him softly on the lips, the forehead. "And for this."

He takes a step back and if Remus tries to get up to follow him, he won't be able to. Regulus' smile now is sad and he takes in Remus' face like he never wants to forget it. "I can't let you stop me. I'm sorry. It will wear off eventually, but I need time to say goodbye to Sirius and to get to where I'm going." Something pained crosses his face, but he reins it in. "Please forgive me, but don't try to follow me. Just... Go to Dumbledore, tell him what I said. Please."

He surges forward for one more kiss. "I love you."