Question Summary:
Hurmat al-Musaharah (incest).

Question Detail:

Is this zina or insest? Will I be forgivven for this acts? How to repent for this acts? It is not one but many
1. I tried touching my mothers and sisters nipples when theywere sleeping at night.
2. I played (rubbed my face) on my sisters thighs and calf (lower leg). I didnt touch her groin area (hidden by her underwear).
Please do tell me was it a category under zina? How should I repent?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Brother in Islam,
Although the acts in question will not constitute zinā[1], such intimacy with family members is nothing less than a highly reproachable act in the eyes of Shari'ah. As such, it is necessary that you truly repent to Allah Ta'ālā for committing such deeds and make a firm intention to never repeat such heinous acts again. The fact that you feel remorse over your actions is the first step towards making true tawbah and achieving forgiveness from Allah the Almighty. You should also make an effort employ certain deterrents that will cut you off from this sin and aid you in furthering yourself from committing this evil deed again in the future.
We also recommend that you perform Salat at-Tawbah[2]:
Salāh at-Tawbah is a simple two rak'āt salāh that is performed in order to secure the forgiveness of Allah Ta’ālā. When one intends to perform this salāh, he should make his wudu properly.[3] Thereafter, he should make an intention for a two rak'āt salāh. This salāh will be prayed like any regular nafl salāh; therefore, one may choose to recite whichever surah one wants to along with surah al-Fātihah. On completion of the salāh, raise the hands for du'ā, show khushū' and khudū' and cry in front of Allah the Almighty while asking Him for forgiveness.[4]
Before we conclude, it is important to take note that the acts that you committed may have certain Shar'ī implications regarding the nikāh of your mother with your father. As such we will need clarification on the following points:
(1) You stated that you "tried" to make inappropriate advancements towards your mother. Does this mean that you stopped yourself from actually committing any misdeeds with her and didn't actually do it?
(2) If you did, did you have contact with your mother's bare skin, or was she wearing clothing at the time?
(3) If she was wearing something at the time, was it clothing made from thick or thin material?
And Allah Ta’āla Knows Best
Bilal Mohammad
Student Darul Iftaa
New Jersey, USA 
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net