Is It Good To Swallow Vaginal Fluids During Cunnilingus?

hello doctor Me and my wife are free from any STD and would like to ask you some sexual question. 1.Is it allowed or good for male partner to swallow the vaginal fluid during oral sex. 2.As I found in lots of your reply not to wash the vagina frequently as it may remove the protective layer ,so how to maintain the good hygiene practice to stay safe for having sex and oral sex. 3. untill when during pregnancy male partner can have sex with her pregnant wife .I mean when we have to stop having sex during pregnancy.