How would I increase/decrease latency?

[PhonixMonk]

Hello.

I have a question, I'll start by giving a brief bit of info as to where this question would relate to:

I play quite a few online games, which increase my latency quite abit, I don't neccessarily have a problem with this, only sometimes it becomes too high.

So, I've come here to ask "How can I change my latency to my preferences?", I don't want my latency to be as low as possible, which sometimes does happen, but on some games it is required to experience 'lag' to perform better, as some games I play can become frustrating due to 'lag' from other players, which enables them to avoid damage and such while still inflicting it... so I would like to know how I would increase my latency also.

If anyone could help me on this, I'd appreciate it.
I'd just like info on how I'd increase/decrease my latency, or if anyone knows of an application I could download, I'd be greatful if they wouldn't mind posting it.