1. I want to say unnecessary things to him/her.
我总想跟他/她唠叨琐碎的事情。

You know it's unnecessary…but you want to meddle!
虽然知道都是些鸡毛蒜皮的事情，可你就是忍不住要跟他/她说！

2. I want to talk about myself in front of him/her.
在他/她面前，我总想谈论自己。

Were there times when you noticed that you kept talking about yourself?
有没有发现，有时你一直在滔滔不绝谈论自己？

3. To be honest, I want to have sex.
说实话，我想要他/她。

No explanation is necessary. It's a human nature.
无须解释了——性乃人之本性嘛。

4. I want to do snowboarding (or other sports) with him/her.
我想和他/她一起滑雪（或做其他运动）。

You want to release your overflowing passion.
你想释放汹涌澎湃的激情。

5. I want to seduce him/her or want to be seduced by him/he.
我想和他/她调情。

You probably are imagining what's next already. (laughs)
或许你都能想象到调情后干什么了。（窃笑）