Well, lavar is not reflexive for itself, you can wash your car (Lavar el coche). The verbs turn into reflexive -when the action affects directly the person(s) who is/are performing it-. Say you wash your hands, the action of washing is performed by you and affecting you. Say you sit in the sofa, the action of sitting is performed by you, and also the consequences affect just you. This is applicable to all I you we they he she it. If a woman (she) performs an action that affects directly and only her, again reflexive. If a group (they) performs an actions that affects directly themselves, same story. Etc, etc. In those situations the conjugation changes. Yo me lavo las manos Tu te lavas las manos El se lava las manos Nosotros nos lavamos las manos Vosotros os lavais las manos Ellos se lavan las manos Now take going to bed as an example. Yo me acuesto Tu te acuestas El se acuesta Nosotros nos acostamos Vosotros os acostais Ellos se acuestan If you see, the verb remains the same reffering to conjugation. What changes for reflexive form is that, according to the case, 'me', 'te', 'se', 'nos', 'os', or 'se', will be added. Hope its clear, Alejo. REF.: I'm a Spanish Teacher.

Hi Leonid. We use "me" because, as Marta said, they're reflexive verbs (The subjtec and the object are the same: me). There's some help: http://www.practicingspanish.com/grammar19.html

mano es femenino, es decir la mano. El plural sería las manos. Se dice me siento en el sofá porque sentar es un verbo reflexivo.