Randomly select between sub and super-scripts for ends and coends.

end_coend.tex

\documentclass{minimal}
% Help from https://tex.stackexchange.com/a/116198

\ifnum\numexpr\pdfuniformdeviate 2\relax<1\relax
	\newcommand{\End}[1]{\int_{#1}}
	\newcommand{\coEnd}[1]{\int^{#1}}%
\else
	\newcommand{\End}[1]{\int^{#1}}
	\newcommand{\coEnd}[1]{\int_{#1}}%
\fi

\begin{document}
Let us test: \(\End{c\in C} F\) and \(\coEnd{d\in D} G\).
\end{document}