A combination of an electric toothbrush handle having a drive shaft and an attachment mountable to the handle, the attachment comprising: a neck member comprising a toothbrush neck and having an elongated body with a principal axis, the neck member elongated body having a cavity extending within the neck member elongated body from a distal end of the neck member; a slide member having (i) an engagement surface and (ii) a linear displacement surface, opposite the engagement surface; and a guide sleeve member having an elongated body, the guide sleeve member elongated body having a cavity extending within the guide sleeve member elongated body from a distal end of the guide sleeve member, the guide sleeve member further having (i) a first outer surface with an engagement opening disposed inward and transverse to the guide sleeve member elongated body, and (ii) a second outer surface, opposite the first outer surface, that comprises a transition surface, wherein the slide member is adapted for moveable insertion, engagement surface first, within the engagement opening of the guide sleeve member and extendable within the guide sleeve member cavity, the guide sleeve member together with moveably inserted slide member being adapted for moveable insertion, proximal end first, within the cavity of the neck member, wherein responsive to insertion of the drive shaft into the cavity of the guide sleeve member together with the moveably inserted slide member within the cavity of the neck member from (a) a first radial position along an axis offset and parallel to the principal axis to (b) a second radial position in-line with the principal axis, via the transition surface, the drive shaft is held in frictional contact with the engagement surface of the slide member to enable a reliable transfer of at least one of force and motion from the drive shaft to the neck member. a neck member comprising a toothbrush neck and having an elongated body with a principal axis, the neck member elongated body having a cavity extending within the neck member elongated body from a distal end of the neck member; a slide member having (i) an engagement surface and (ii) a linear displacement surface, opposite the engagement surface; and a guide sleeve member having an elongated body, the guide sleeve member elongated body having a cavity extending within the guide sleeve member elongated body from a distal end of the guide sleeve member, the guide sleeve member further having (i) a first outer surface with an engagement opening disposed inward and transverse to the guide sleeve member elongated body, and (ii) a second outer surface, opposite the first outer surface, that comprises a transition surface, wherein the slide member is adapted for moveable insertion, engagement surface first, within the engagement opening of the guide sleeve member and extendable within the guide sleeve member cavity, the guide sleeve member together with moveably inserted slide member being adapted for moveable insertion, proximal end first, within the cavity of the neck member, wherein responsive to insertion of the drive shaft into the cavity of the guide sleeve member together with the moveably inserted slide member within the cavity of the neck member from (a) a first radial position along an axis offset and parallel to the principal axis to (b) a second radial position in-line with the principal axis, via the transition surface, the drive shaft is held in frictional contact with the engagement surface of the slide member to enable a reliable transfer of at least one of force and motion from the drive shaft to the neck member.