One possibility that I think might be worth considering on this theme is the use of a device called a Tetherspout (you will need to google it). The guy who designed it is very inventive. The device has the advantage that once installed it isn't going to escape (e.g. during ejaculation) and being hollow allows you to cum through it with only modest restriction.
I have made one to test as an anti pull-out device for a chastity cage (for which it seems perfect) but it seems to have many other possibilities that would otherwise require a piercing (which is something I'm not going in for!)