Day Questions

Is it allowed to have any manner of sex with your wife? And what are the restrictions for sex with wife?

There are no religious restrictions on the types of sexual relationship that can be enjoyed between husband and wife.

Most of the time while performing prayers of four rak'a, I forget which rak'a I was performing, whether it was the third or the fourth. In such a situation what can I do?

You should assume it is the fourth rak'a. And after finishing the prayer with Tasleem, you should perform a prayer of one rak'a - as the prayer of precaution - in which only Surah al-Fatiha is recited, and then you bow down, prostrate twice, and end with Tashahhud and Tasleem. Alternatively, you can perform this prayer as explained in two rak'as while in the sitting position.