I'd like to say I really appreciate the help you've already given me by this site. Right now I'd like to know what the Bible says, or at least your opinion, on some of the issues I'm facing.
My first issue is my habit of browsing and sometimes looking up sexual content (not porgnography, just topics). It seems whenever I go to teen-forums I always end up in the puberty, 16+ topics, looking at size-threads, "how many times a day", "boobs or ass", "shave or trim", and other stuff like that. I don't look at any of the really gay or obviously wrong stuff (like fingering, favorite porn, favorite sex moves, etc.) but sometimes I do look at mutual masturbation threads (which is probably the most akward one I've ever seen). I sometimes get erections when browsing, but they don't lead me to masturbation, and if I do masturbate after, I make sure I'm not thinking about anything (quite seriously), so I'm confident that I'm not using it to stimulate me, or masturbate to, or anything like that. I feel sort of guilty and delete the history on some of the weirder topics (and even some questions I've looked at here). I sometimes look up word definitions that I already know the meaning of and I don't know why. I try to have devotionals daily, and fill my mind with pure things, but every now and then I look up this kind of stuff, or end up finding it, and I don't think it could be classified as "pure". An example would be I'm looking up a good poll or debate on a teen-forum and then end up clicking on a "do you sleep nude" thread. I think it's wrong because I don't want anyone to see me doing it, but then again I don't want people seeing me using the bathroom or masturbating either. So I'd like to know, is it wrong to look at this content?
Secondly, I know a lot of straight guys that compare, jack off, and talk about sexual stuff with each other at school, and I do sometimes. I'd like to know if it's OK to talk to your friends about this kind of stuff and if it's OK to compare. I know that jacking off with each other is wrong because it's homosexuality, and it would just be too akward for me. But sometimes I do compare when they ask me, and talk about other sexual things. This would also extend to when my friends and I are talking about girls, and one of them would ask who would you most like to have sex with, and I say "none", but they say "not really but just if you had to," and stuff like that. I'm pretty sure most of my friends are Christians, but somehow out of nowhere these discussions pop up.
The curiosity about your body and sex is understandable. You get something new and you want to know all about it. You want to know if you are normal or if other people experience the same things you are experiencing. But there is a fine line between curiosity and sensuality when it comes to the human body. Sensuality is when you look at things because it makes you sexually aroused.
The Internet contains a lot of information, but not all of it is good information. There are people who capitalize on the novelty and awkwardness of becoming an adult as a way to promote immorality. Even properly done information can become wrong if the person isn't so much interested in the information as he is looking for a way to get himself sexually aroused.
"For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust, like the Gentiles who do not know God" (I Thessalonians 4:3-5).
Though you try not to get into the things that obviously designed to stimulate lust, you do poke around the edges. Though you don't masturbate to it, you make it clear that you go looking because it sexually arouses you. Some deal with topics that you know is morally wrong, such as the mutual masturbation. What may have started out as curiosity has moved beyond that.
What you are losing is your sense of shame. It is still there, but you've been giving it a beating. "And have no fellowship with the unfruitful works of darkness, but rather expose them. For it is shameful even to speak of those things which are done by them in secret" (Ephesians 5:11-12). People do put much more private things on the Internet because it gives them a sense of anonymity. But there is a reason private things should be kept private. You should have respect for your friends, not asking to see their genitals or agreeing to show them yours.
"But fornication and all uncleanness or covetousness, let it not even be named among you, as is fitting for saints; neither filthiness, nor foolish talking, nor coarse jesting, which are not fitting, but rather giving of thanks. For this you know, that no fornicator, unclean person, nor covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God. Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not be partakers with them" (Ephesians 5:3-7).
Having sex outside of marriage is sinful; therefore, talking about having sex with girls is wrong because it gives credence to sin. Notice the "not really but if you had to." Since when is any sin a "must." God tells us that there is always a way out of temptation that doesn't require a person to sin (I Corinthians 10:13).
It comes down to recognizing that sin remains sinful no matter how it is justified.