slowly (but steadily); gradually; bit-by-bit
irritatedly; impatiently
scorchingly (of the sun)
sizzling (i.e. sound of frying in oil)
sound of a warning bell, alarm clock, etc.
oozing out (oil, sweat, etc.); seeping out
気温がじりじり上がっている。
The temperature is rising gradually.
太陽がじりじり照りつけていた日だ。
It was a day when the sun beat down mercilessly.
じりじりと追い詰められました。
I was gradually cornered.