diff --git a/src/lazy_blocks_vec.rs b/src/lazy_blocks_vec.rs
index 887e2f8..743b7e4 100644
--- a/src/lazy_blocks_vec.rs
+++ b/src/lazy_blocks_vec.rs
@@ -14,9 +14,8 @@ impl<T, const ELEMENTS_PER_BLOCK: usize> LazyBlocksVec<T, ELEMENTS_PER_BLOCK> {
     }
 }
 
-// todo: allow non-default construction
-impl<T: Default, const ELEMENTS_PER_BLOCK: usize> LazyBlocksVec<T, ELEMENTS_PER_BLOCK> {
-    pub fn get_or_create_default(&mut self, index: usize) -> &mut T {
+impl<T, const ELEMENTS_PER_BLOCK: usize> LazyBlocksVec<T, ELEMENTS_PER_BLOCK> {
+    pub fn get_mut(&mut self, index: usize) -> &mut Option<T> {
         let block_index = index / ELEMENTS_PER_BLOCK;
         let blocks_len = self.blocks.len();
 
@@ -27,7 +26,7 @@ impl<T: Default, const ELEMENTS_PER_BLOCK: usize> LazyBlocksVec<T, ELEMENTS_PER_
         }
 
         let block = self.blocks[block_index].get_or_insert_default();
-        block.data[index - block_index * ELEMENTS_PER_BLOCK].get_or_insert_default()
+        &mut block.data[index - block_index * ELEMENTS_PER_BLOCK]
     }
 }
 
@@ -53,11 +52,11 @@ mod tests {
         let mut vec = LazyBlocksVec::<i32, 8>::default();
 
         {
-            let elem = vec.get_or_create_default(1);
-            *elem = 1;
+            let elem = vec.get_mut(1);
+            *elem = Some(1);
         }
         assert_eq!(vec.blocks.len(), 32);
-        assert_eq!(vec.get_or_create_default(1), &1);
-        assert_eq!(vec.get_or_create_default(2), &0);
+        assert_eq!(vec.get_mut(1), &Some(1));
+        assert_eq!(vec.get_mut(2), &None);
     }
 }
diff --git a/src/tls.rs b/src/tls.rs
index 8ecea9f..95962d7 100644
--- a/src/tls.rs
+++ b/src/tls.rs
@@ -16,7 +16,7 @@ pub type TlsVec<T> = LazyBlocksVec<Arc<T>, 32>;
 pub type TlsRegistry<T> = LocalKey<RefCell<TlsVec<T>>>;
 
 pub struct EnumerableTls<
-    T: Default + 'static,
+    T: 'static,
     IdProvider: GlobalProvider<Mutex<FreeIds>>,
     TlsProvider: GlobalProvider<TlsRegistry<T>>,
 > {
@@ -26,7 +26,7 @@ pub struct EnumerableTls<
 }
 
 impl<
-    T: Default + 'static,
+    T: 'static,
     IdProvider: GlobalProvider<Mutex<FreeIds>>,
     TlsProvider: GlobalProvider<TlsRegistry<T>>,
 > Default for EnumerableTls<T, IdProvider, TlsProvider>
@@ -37,7 +37,7 @@ impl<
 }
 
 impl<
-    T: Default + 'static,
+    T: 'static,
     IdProvider: GlobalProvider<Mutex<FreeIds>>,
     TlsProvider: GlobalProvider<TlsRegistry<T>>,
 > EnumerableTls<T, IdProvider, TlsProvider>
@@ -50,19 +50,6 @@ impl<
         }
     }
 
-    pub fn get_or_create(&self) -> Arc<T> {
-        let wrapper = TlsProvider::global()
-            .with_borrow_mut(|blocks| blocks.get_or_create_default(self.tls_id.inner()).clone());
-
-        {
-            let mut guard = self.all_tls.lock().unwrap();
-            guard.push(Arc::downgrade(&wrapper));
-            guard.retain(|wrapper| wrapper.upgrade().is_some());
-        }
-
-        wrapper
-    }
-
     pub fn for_each(&self, mut f: impl FnMut(Arc<T>)) {
         let mut wrappers_guard = self.all_tls.lock().unwrap();
         wrappers_guard.retain(|wrapper| {
@@ -76,6 +63,33 @@ impl<
     }
 }
 
+impl<
+    T: Default + 'static,
+    IdProvider: GlobalProvider<Mutex<FreeIds>>,
+    TlsProvider: GlobalProvider<TlsRegistry<T>>,
+> EnumerableTls<T, IdProvider, TlsProvider>
+{
+    pub fn get_or_create(&self) -> Arc<T> {
+        self.modify(|wrapper| wrapper.clone())
+    }
+
+    pub fn modify<U>(&self, mut f: impl FnMut(&Arc<T>) -> U) -> U {
+        TlsProvider::global().with_borrow_mut(|blocks| {
+            let wrapper = blocks.get_mut(self.tls_id.inner());
+            let register = wrapper.is_none();
+            let wrapper = wrapper.get_or_insert_default();
+
+            if register {
+                let mut guard = self.all_tls.lock().unwrap();
+                guard.push(Arc::downgrade(wrapper));
+                guard.retain(|wrapper| wrapper.upgrade().is_some());
+            }
+
+            f(wrapper)
+        })
+    }
+}
+
 #[macro_export]
 macro_rules! declare_enumerable_tls {
     ($TlsType:ident, $Data:ty) => {
@@ -111,13 +125,13 @@ mod tests {
 
     use static_assertions::assert_impl_all;
 
-    declare_enumerable_tls!(MyEnumerableTls, AtomicI32);
-
-    assert_impl_all!(MyEnumerableTls: Send, Sync);
-
     #[test]
     fn test() {
-        let tls = MyEnumerableTls::new();
+        declare_enumerable_tls!(TestEnumerableTls, AtomicI32);
+
+        assert_impl_all!(TestEnumerableTls: Send, Sync);
+
+        let tls = TestEnumerableTls::new();
 
         let sum_data = || {
             let mut sum = 0;
@@ -151,4 +165,24 @@ mod tests {
         sleep(Duration::from_millis(20));
         assert_eq!(sum_data(), 1);
     }
+
+    #[test]
+    fn get_twice() {
+        declare_enumerable_tls!(GetTwiceEnumerableTls, AtomicI32);
+
+        let tls = GetTwiceEnumerableTls::new();
+
+        let data0 = tls.get_or_create();
+        data0.fetch_add(1, Ordering::SeqCst);
+
+        let data1 = tls.get_or_create();
+        data1.fetch_add(1, Ordering::SeqCst);
+
+        let mut sum = 0;
+        tls.for_each(|data| {
+            sum += data.load(Ordering::SeqCst);
+        });
+
+        assert_eq!(sum, 2);
+    }
 }