In response to the controversy over the use of language to refer to WhatsApp service, the Royal Academy of Language accepts as valid guasap words guasapear guasaps and the name of the popular instant messaging service.
The terms can be used without adding quotation marks because it is recognized as suitable for the Spanish adptaciones. The BBVA Fundéu notes that the letter “w” is pronounced as “gu” in Spanish, for example polo and web.
The plural of “wasap” is “wasaps”, without accent, despite ending in “s”, as it is a sharp word ending in consonant cluster. You can even apply the term guasapear when you want to apply to several persons.
Separately, the Fundéu BBVA, working in consultation with the Royal Spanish Academy, indicates that although they may also be eligible adaptations “guasap” plural “guasaps” and “guasapear” to be perceived as more colloquial, the ways are preferred “w”.