Removing unwanted hair

Q: Removing hair from the back passage is very difficult, as i cannot see. At times najaasat gets stuck to the hair since it is long in that area. How can I cut it easily?

Q: What is the correct method of removing unwanted hair?

Q: Please could you advise the extent of removal of pubic hair. From the navel or from the pubic hairline? Scrotal hair? Area between the scrotum and back passge? Around the back passage? Also, what is the absolute maximum time that a person can go without removing such hair and is it a sin to go beyong this period?