Sit on (eggs) (8)
I believe the answer is:
incubate
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sit on eggs</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for incubate that I've seen before include "Help eggs to hatch" , "nurture" , "Sit on (eggs)" , "Brood" , "Develop under favourable conditions, bacteria say" .)