My dad gave me similiar advice to what your friend says..
if you are really feeling somebody and desire to have sex with them sooner than later is better because then you will know if he is trying to just get sex or if he is really into you depending on how he acts afterwards....he was real clear that this was not a anybody you meet situation...somebody you are feeling who you know you want to have sex with anyways...if you are not even sure you want him or not trippin too much off of him, not sexually attracted to him etc... don't let him make sex an issue or something you are pressured into doing... do it on your own time if you ever decide to go there...he was always on being in control of your body and doing things for reasons that suit you and for everybody things are different....in his day he has never referred to a woman in a derogatory manner ,but he got his swerve on and he says he can only recall a couple of women who weren't emotionally jacked up over sex and most were having it not because they really wanted to but for a whole host of other reasons and motives that usually caused them grief in their lives, or wanting to and feeling extremely guilty over it and there was really not much of a difference of the emotional stability of the women around sex whether they acted like they were so super sexual and loved having sex and giving it up quick or making him "wait"
one of the reasons he was always so open about sex and adamant about me holding all the power and to always be accountable and responsible for any decisions I make regarding it, know the consequences that can occur and to always know my motives behind my decisions when it comes to dealing with men and having sex....
enjoy who you are with and do it because you want to/when you want to and enjoy doing it and always take responsibility for any outcome that may occur...if you start doing it for other reasons or to try and get something back from a man then thats where all the emotional problems come in
the beauty and the curse with that was men 9xoutta 10 loved it (being sexually open even if we didn't have/never had sex) and were always like "you're the one" and then would make me the person who was either responsible for their total happiness or the person who could destroy their world, and it seemed I was doing alot of destroying of worlds by not wanting to be with them how they wanted to be with me
on one end its a nice ego booster and my ego did get boosted, however on the other end I was starting to hold myself responsible for "hurting" other people and I went from being super open, to super closed off (which sucked btw) to really just in the past few years figuring out a balance to being myself and taking into account how other people, esp men handle me and not creating more drama on my end of their end
the men i have been involved with and have a deep love and still deep relationships with are men i had sex with fairly early on in the relationship....people aren't that hard to read, even with excessive fronts up...people are very transparent when you stop paying attention to external factors and pick up on their energy...their whole self is revealed, which is what most people spend alot of time doing in the "getting to know stage" attempting to get to the core of a person, which in alot of cases people still don't after years of "knowing" somebody