Touch is very important to the Sangheili, as is evidenced by the fact that they despise being touched by Humans. However, it is just the opposite when it comes to family members.
Nuzzles are an example. They are common amongst friends and family, a somewhat universal gesture. The most intimate form of the nuzzle is when two Sangheili rub their mandibles together; this is mostly done between lovers, but can also be done between parent and child or between long-time friends. An example of the latter is if two friends have not seen each other for a long time; they will rub mandibles together to re-familiarize themselves with the other's scent, put their own scent on the other, and reaffirm their bond.
Nips can mean a variety of things. They can mean 'get moving', 'stop that', serve as a reprimand, and even be sensual. The most common places for nips are the back or nape of the neck. Most often, as suggested, nips hold an aggressive meaning, and they ar