It is undesirable to talk excessively during intercourse. Talk should be limited to bare necessity. Islam advocates dignity even at such occasions. Faqih Abul-Laith Samarqandi writes in his book BUSTAN that excessive speech during coitus could be the cause of dumbness in the off-spring to be. This habit should be shunned.
It is undesirable for both the partners to look at each others genitals. The author of SHRATUL-ISLAM writes that looking (habitually) at the private parts of the woman could result in blind off-spring.
Although it is permissible for the husband and wife to look at every part of each others’ anatomy, it is an undesirable act from the moral point of view. Rasulullah (Sallallahu-Alayhi-Wasallam) never looked at Hazrat Aisha (Radiyallahnu-Anhum), nor did she look at him (at the private area).
Many of the Ulema are of the opinion that looking at the wife’s gentials causes the eye- sight to weaken.