companion in one's pleasures; hobby buddy
Refers to a friend or companion with whom one shares a hobby, pastime, or pleasurable pursuit. Often implies a shared interest in something enjoyable or indulgent.
He often goes out on weekends with his fishing buddy.
I enjoy playing Go with my hobby companions.
趣味仲間 is a more neutral term for a friend who shares a hobby, while 道楽仲間 can carry a nuance of indulgence or a more passionate, sometimes even slightly disreputable, pursuit.
Compound of 道楽 (どうらく, 'hobby, pastime, dissipation') and 仲間 (なかま, 'companion, friend').