\version "2.16.2"
slashOn = {%\override Flag #'stroke-style = #"grace"
        \override Stem #'stencil = #(lambda (grob)
                (let* ((x-parent (ly:grob-parent grob X))
                        (is-rest? (ly:grob? (ly:grob-object x-parent 'rest))))
                (if is-rest? empty-stencil
                        (ly:stencil-combine-at-edge
                                (ly:stem::print grob)
                                Y
                                (- (ly:grob-property grob 'direction))
                                (grob-interpret-markup grob
                                        (markup
                                        #:translate '(-0.75 . 0)
                                        #:draw-line '(3.5 . 2)))
                                 -4 ))))        
}
%\once \override Stem #'extra-offset = #'(-1 . -1)
slashOff = {
        \revert Stem #'stencil
        %\revert Flag #'stencil
        }
        
\relative c {                              
\clef bass
\stemUp \slashOn  cis!8-._\markup {\dynamic pp \italic "sempre, misterioso"} [\slashOff e-.] s \breathe \times 2/3 {\slashOn \once \override Accidental #'transparent = ##t g-.[\slashOff e-.] s \breathe}  
\times 2/3 {\slashOn a-. [\slashOff c-. a-.] } 
}