drinking at one’s own home; similar in meaning to '家飲み' (having drinks at home rather than going out)
寒い夜は自宅飲みで温かい鍋をつついた。
On cold nights we drink at home and share a hot pot.
自宅飲みなら時間を気にせずゆっくりできる。
If you drink at home, you can relax without watching the time.