Is nursing four separate times for 15 minutes each time considered prohibitory suckling, and is the strong presumption of having reached five prohibitory nursings considered (sufficient)?

The suckling that establishes prohibition (of marriage) consists of five known sucklings within two years (of age). A suckling is defined by common practice (urf): it is when the child takes the breast, sucks from it, and then leaves it, turning away. If this occurs five times, the prohibitive suckling is established. A suckling is not defined by time. When there is doubt about the number of sucklings or their timing, the default is non-prohibition. However, caution is recommended, especially concerning marital relations.