This article is an excerpt from our Sefer
11. Nursing child awake:
One who has a nursing child is not to have marital relations while the child is awake. [Some Poskim, however, explain that this is simply good advice and is not an actual prohibition.]
 M”A 240:29; Zohar Parshas Vayikra p. 119a; Bedek Habayis in name of Zohar ibid; Kitzur SHU”A 150:16; M”B 240:54; Kaf Hachaim 240:91; Taharas Yisrael 240:87-88; Piskeiy Teshuvos 240:29; Sheyikadesh Atzmo [Nachmonson-2015] p. 317
 Vaya’an Yosef 78; Divrei Yatziv 1:104; Piskeiy Teshuvos ibid; See Beir Heiytiv and other Achronim in 240 who omitted this part of the Zohar, even though they recorded the later ruling regarding nursing after intercourse; See also Sheyikadesh Atzmo 25:1 that if she has a bottle prepared for the child then they may have intercourse even if the child is awake.