Assalaamu alaykum. This is a hadith from Sahih Bhukhaari, Volume 1, Book 10, Number 558: Abu Hurayrah narrated that the Messenger of Allaah, sallallaahu 'alayhi wa sallam, forbade two kinds of sales, two kinds of dresses, and two prayers. He forbade offering prayers after the Fajr prayer till the rising of the sun and after the 'Asr prayer till its setting. He also forbade "Ishtimaal-Assama" and "Al-Ihtiba" in one garment in such a way that one's private parts are exposed towards the sky. He also forbade the sales called "Munabadha" and "Mulamasa".
My questions are:
1. What are "Ishtimaal-Assama" and "Al-Ihtiba"?
2. What are the examples in this modern period?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

The scholars differed in opinion about the meaning of Ishtimaal as-Sammaa’; the linguists said: it is to wrap one’s body with a garment in a manner that one cannot take his hands out of it.

The jurists said: it is to cover oneself with one garment only without any other clothing on him, then he puts one of its edges over one shoulder.

An-Nawawi said in Sharh Muslim:

"According to the interpretation of the linguists, it is disliked to wrap oneself in the way that is mentioned because if there was a need for him to push an animal or insect or the like, it is difficult for him to do so, or he will not be able to do so at all, so he may be harmed. According to the interpretation of the jurists, wrapping oneself in the manner described above is forbidden if this leads to revealing part of his ‘Awrah (parts of the body that must be covered in Islam); otherwise it is disliked."

Ibn 'Uthaymeen saidin Ash-Sharh Al-Mumti':

“Ishtimaal as-Sammaa’ is to be wrapped up with a garment without being able to take one’s hands out of it because this prevents one from performing the legislated actions of the prayer and because if something attacks him, then he is unable to be quick to repel it, especially if this garment is a Qamees (long shirt), then the matter is even worse, meaning to wear the Qamees without putting his hands inside the sleeves; this is Ishtimaal as-Sammaa’, because another garment (open at the front) may open with a powerful movement whereas this Qamees won't open.

Some scholars said: Ishtimaal as-Sammaa’ means to make Idhtibaa’ while wearing only one garment. Idhtibaa' is for a person to expose his right shoulder and put the left edges of his garment under his left armpit, meaning to have a loose garment and make Idhtibaa’ with it. It is disliked to dress in this manner [while having only one garment to cover the whole body and not two separate garments for the upper part of the body and another one for the lower part of the body]; as the garment might fall and thus disclose his ‘Awrah, and if one really fears that his ‘Awrah might be exposed, then it is forbidden.

It was also said: it is to put the garment over his head and then let it fall all over his body to his feet.

So these are the three ways of Ishtimaal as-Sammaa’; if you look at all these forms closely, you will find that they are contrary to the saying of Allah (which means): {O children of Adam, take your adornment at every masjid...} [Quran 7:31] It is a kind of negligence in being clothed in an Ishtimaal as-Sammaa’ way, whereas taking the entire adornment is to wear the garment in a way that all the people are used to wearing it, and in a manner that covers the body properly and is familiar and usual." [Abridged]

As regards al-Ihtibaa’, An-Nawawi said, "It is for a man to sit on his buttocks and erect his legs together (sticking them to the stomach) while tying them with a garment or holding them with his hands. This was the custom of the Arabs (the way they used to sit) in their meetings, but if part of his ‘Awrah is exposed, then it is forbidden."

Awn Al-Ma’bood Sharh Sunan Abu Daawood reads, "Al-Ihtibaa’ is for a man to sit on his buttocks and erect his legs together while tying them with a garment or holding them with his hands; this is the custom of the Arabs. This was the custom of the Arabs. (with no part of the garment to cover his private parts), i.e. his private parts are exposed to the sky. So if the private parts are exposed, it is forbidden, otherwise no.”

Therefore, the examples of Ishtimaal as-Sammaa’ and al-Ihtibaa’ in modern times are the same as in the old times. If a person is wrapped with one garment while he is not wearing any other clothes, then it is Ishtimaal as-Sammaa’; and if one sits on his buttocks with his bent legs erect while there is no part of the garment to cover his private parts (i.e. they are exposed to the sky), then this is the Ihtibaa’ that is forbidden.

Allah knows best.