The tugging of his hair only eggs Thorin on, the slight pull at his scalp from it keeping him where he is. He's fine with it, he is more than willing to lavish more of Frerin's chest with his mouth. Kisses and nips start trailing downward, following the path of hair till he kisses just under his naval.

"Say it again." He'll breathe out, another kiss, lower.

"Tell me what you want, Frerin." His mouth won't touch what he's sure his brother would like, instead he'll kiss along the inner part of a thigh, his hand still working the now hardened shaft in his fingers.