Conclusion: We do not know of anything in the religious texts to indicate that it is mustahabb to have intercourse with one’s wife on Friday night.

Summary of the answer: The way this phrase is to be pronounced is “wa ta‘aala jadduka” with a fat-hah on the jeem, according to scholarly consensus, and what is referred to is greatness. It is not permissible to pronounce it with a kasrah on the jeem (jidduka), because this is distorting the words of the Messenger, who (blessings and peace of Allah be upon him) pronounced it with a fat-hah and the scholars did not refer to any alternative pronunciation.