pleasantly; comfortably
彼を気持ちよく迎えてあげようよ。
Let's give him a warm welcome.
何杯か飲むと、その男は酔って気持ちよくなった。
After a few drinks, the man got drunk and started feeling good.
余計なことを言わなければ―皆気持ちよく金がもらえる
If you don't say anything unnecessary—everyone can get paid without any trouble.
— es[エス] (2001)
昨夜は気持ちよく眠れたよ。
I slept well last night.