The noun intravaginal ejaculation latency time can be countable or uncountable.

In more general, commonly used, contexts, the plural form will also be intravaginal ejaculation latency time.

However, in more specific contexts, the plural form can also be intravaginal ejaculation latency times e.g. in reference to various types of intravaginal ejaculation latency times or a collection of intravaginal ejaculation latency times.