Our Gemara begins by discussing the difficulties caused by taking nedarim lightly and segues to a discussion of other things that must be taken seriously. Several of the issues discussed have to do with appropriate behavior when men interact with women, including a discussion of propriety during marital intercourse.
the Gemara quotes Rabbi Yohanan, who teaches that the cases mentioned below are a da’at yahid – they only are the view of Rabbi Yohanan ben Dehavai:
Rabbi Yohanan ben Dehavai said: The Ministering Angels told me four things: People are born lame because their parents “overturned their table” [i.e., practiced unnatural cohabitation]; dumb, because they kiss “that place”; deaf, because they converse during relations; blind, because they gaze at “that place”.
Rabbi Yohanan ben Dehavai’s views notwithstanding, the Sages rule that the halakha does not follow Rabbi Yohanan ben Dehavai, rather a man may do whatever he pleases with his wife during sexual relations.
The Gemara continues by quoting Ameimar, who said:
Who are the ‘Ministering Angels’? The Rabbis. For if we understand it literally, why did Rabbi Yohanan say that the halakha does not follow Rabbi Yohanan ben Dehavai, given that the angels know more about the formation of the fetus than do we? And why are they designated ‘Ministering Angels’? – Because they are as distinguished as they.
According to some opinions, Talmud scholars are considered as distinguished as angels because they wore unique clothing that made them stand out from the rest of the people. Such clothing was popular amongst the scholars of Bavel, but was not worn in Israel. According to Rashi, the scholars were distinguished in that they wore a tallit with tzitzit at all times. This clothing was the clothing of the angels, as is clear from Sefer Daniel, where the angel is referred to as ha-ish lavush ha-badim – the man clothed in linen (see Daniel 12:7).