\documentclass{article}
\usepackage{amscd}
\usepackage{tikz-cd}
\usepackage{folarrow}
\folarrowsetup{gap=0.45}  % whole document: slightly wider spacing of the strokes
\begin{document}
\[
\begin{CD} E\\ @FVV{\pi}V\\ M \end{CD}
\qquad
{\folarrowsetup{span=1.5, lean=0.5}  % only inside this group
\begin{CD} E\\ @FVV{\pi}V\\ M \end{CD}}
\qquad
{\folarrowsetup{thickness=0.8pt}
\begin{tikzcd} E \arrow[d, foliated, "\pi"] \\ M \end{tikzcd}}
\qquad
\begin{CD} E\\ @FVV{\pi}V\\ M \end{CD}
\]
$E \folrightarrow M$,
{\folarrowsetup{shift=0.5}$E \folrightarrow M$},
$E \folrightarrow M$
\end{document}