Ashikase has a new app in Cydia called Last App. It keeps track of your most recent app and allows you to switch quickly between it and the foreground app. Optionally it will background the current app when switching. It's perfect for playing a game while chatting with friends on Beejive or for quickly checking that tutorial without losing your place in Settings. Activation is through libactivator, so there are plenty of ways to invoke it. I've got mine to switch on swipe-in from bottom-right. Ashikase has also made Kirikae libactivator compatible, so it can be similarly activated. I've now got Kirikae set to invoke on swipe-in from bottom-left. Much faster than holding home.